Preparation and Characterization of Thermoplastic Starch Mixed with Waterborne Polyurethane
Qiangxian Wu and Lina Zhang*
Department of Chemistry,Wuhan University,Wuhan430072,China
A polyester-type waterborne polyurethane(WPU)was synthesized with2,4-tolylene diisocyanate
(TDI),poly-1,4-butylene glycol adipate(PBA),and2,2-bis-(hydroxylmethyl)propionic acid
(DMPA).A series of compression-molded sheets coded as STPU were prepared by mixing
thermoplastic starch(TPS)with the desired amount of WPU.The properties and structure of
the sheets TPS,STPU,and WPU were investigated by tensile tests,wide X-ray diffraction
patterns(WXRDPs),differential scanning calorimetry,infrared spectroscopy,ultraviolet spec-
troscopy,and scanning electron microscopy.The results showed that the tensile strength,
breaking elongation,and water resistance of the STPU sheets were all higher than that of TPS,
when the WPU content was in the range from5to30wt%.The STPU sheets were found to
have higher crystallinity than WPU and amorphous TPS and slightly lower light transimitance
than TPS,suggesting that partially recrystallized starch formed.The WPU plays an important
role in the formation of new morphology and in the enhancement of the mechanical properties
of the STPU sheet.The compression-molded STPU sheets provided a potential application in
the field of biodegradable materials.
Introduction
In the past decades,starch has attracted considerable attention because of its low cost,availability from renewable resources and excellent biodegradability,1,2 and it has been used in agricultural mulch,3-5industrial foam,6and food packaging.7In1972,Griffin was the first to use a screw extruder to prepare biodegradable starch-based polyethylene products,such as mulch in agriculture.8However,this blend showed that it is only partial biodegradable.9In an effort to make fully biodegradable starch-based materials,much research has been done recently.Preparation of casting starch films based on edible food and degradable materials have been studied.10-13Moreover,several efforts have been made on the study of thermoplastic starch(TPS), including its composition,14,15molecular mass,16plasti-cizers,17-21and blends.23Processing techniques for TPS mainly include extrusion,kneading,pressure,and injec-tion molding,and the recent studies for TPS focus on its plasticizers such as water19and glycerol.20,21 Polyurethane(PU)materials have been generally used in the automobile,paint,furniture,and textile industries24and also in biomass foam incorporated with renewable raw materials.25Waterborne polyurethane (WPU),as a nontoxic and nonflammable material,has been abundantly used as an environmental coating26,27 and an adhesive,28and it is endowed with excellent properties.In particular,polyester-type WPU not only has excellent mechanical properties,but also has a hydrolytic character,which makes WPU easy to de-grade29,30and,therefore,friendly to the environment. WPU has a potential miscibility with starch because both have hydrophilic groups.Therefore,it is possible to mix WPU with starch to improve the mechanical properties of TPS.In addition,we have successfully prepared biodegradable and water-resistant regenerated cellulose films coated with polyurethane/chitosan31or polyurethane/nitrocellulose.32Furthermore,polyure-thane blends with natural polymers were shown to be easily degraded and metabolized by to be microorgan-isms,leading to the production of CO2,H2O,glucose, aromatic ether,glucopyranose derivatives,and nitrate.33 The miscibility,structure,and properties of blend membranes from cellulose with other polymers,such as casein34and alginate,35were investigated in our labora-tory.The results indicated that their mechanical strength,thermostability,and light transmittance were higher than those of regenerated cellulose film.This suggests that blending is a simple and useful method for improving properties of natural polymers.In this work,an attempt was made to mix thermoplastic starch and WPU to prepare new thermoplastic materials, which can be used in medicine and food field.A polyester-based WPU was mixed with thermoplastic starch and compression-molded with a heating press to obtain an improved TPS.The effect of the WPU content on the mechanical properties,water resistance,thermal stability,and morphology of the TPS/WPU mixture was investigated by tensile tests,wide X-ray diffraction patterns(WXRDPs),differential scanning calorimetry (DSC),infrared spectroscopy(IR),ultraviolet spectros-copy(UV),and scanning electron microscopy(SEM). Experiment
https://www.doczj.com/doc/7a3047824.html,mercial2,4-tolylene diisocyanate(TDI, supplied by Shanghai Chemical Co.,China)was vacuum-dried at80°C for2h and used as hard segments.Poly-1,4-butylene glycol adipate(PBA2000,Mw)2150, supplied by Zhangjing Polyurethane Factory,China) was vacuum-dried at105°C for5h,and used as soft segments.2,2-Bis-(hydroxylmethyl)propionic acid (DMPA,supplied by Chengdu Polyurethane Co.,China), used as the chain extender and anionic center,was vacuum-dried at110°C for2h.Triethylanine(TEA) and acetone,used as the neutralizing reagent and
*Correspondence to:L.Zhang.E-mail:lnzhang@
https://www.doczj.com/doc/7a3047824.html,.Fax:+86-27-87882661.
558Ind.Eng.Chem.Res.2001,40,558-564
10.1021/ie000582t CCC:$20.00?2001American Chemical Society
Published on Web12/20/2000
solvent,respectively,were immersed in 4?molecular sieves for more than a week to become dehydrated before use.DMPA,TEA,and acetone were of analytical grade.Cornstarch containing 23.5%amylose and 75%amylopectin was purchased from Wuhan Starch Co.(China)and vacuum-dried at 105°C for 5h before use.Preparation of Waterborne Polyurethane.An-ionic waterborne polyurethane (WPU)was synthesized according to the acetone process reported by Yang et al.36The ratio of NCO/OH in this case was 1.75.A 500-mL four-necked flask was fitted with a thermometer,a stirrer,and an inlet and outlet of dry nitrogen.PBA2000(70.0g)and DMPA (4.4g)were added to the flask and stirred at 120°C for 15min to easily dissolve the DMPA and then cooled to 85°C.TDI (19.8g)were introduced into the flask under dry nitrogen with a funnel,and the reaction was carried out for 2-3h until the NCO group content reached a given value,which was determined by dibutylamine back-titration.37When the product was cooled to 52°C,80mL of acetone was added to reduce the viscosity of the prepolymer and then neutralized with 3.3g of TEA for 30min.Finally,290g of distilled water was added quickly with vigorous stirring,thus forming WPU after 20min.After being stored in room temperature for a week,the aqueous mixture was concentrated to 60%solid content at 30°C with a rotary vacuum-evaporator to remove residual acetone.The viscosity of the WPU emulsion was measured by a rotational viscosimeter (NDJ-4,Shanghai Balance Fac-tory)to be 52MPas.
Compression Molding.A heat press device was made by our laboratory,and the sketch map is shown in Figure 1.The press device was equipped with a mold,a pair of steel blocks,whose temperature was controlled,and a lab jack with a pressure meter.Starch was mixed with desired amounts of waterborne polyurethane (WPU),namely,5,10,15,20,25,and 30wt %,a series of TPS/WPU mixtures were prepared and coded STPU5,STPU10,STPU15,STPU20,STPU25,and STPU30,
respectively.The pure thermoplastic starch was coded TPS.Finally,water was added to adjust the water content to 33wt %.Every premix was crushed with a mortar and pestle for 30min and then sealed and stored in refrigerator at 5°C for 2days.A pure casting film of WPU was prepared according to our previous work 38and coded WPU.An 8-g sample of starch or a mixture of starch and WPU was placed into the mold and covered with polished stainless steel plate on both sides,and silicon oil was sprayed on the stainless steel plates as a mold oil.The mold was placed between the steel blocks,whose temperature was controlled at 155°C,and then the pressure was quickly increased from 0.5to 15MPa for 1min and kept for 5min at 155°C.After the compression molding,the mold was cooled to room temperature with a fan at a rate of 10°C/min.A transparent sheet was released from the mold and stored at room temperature for a month at a relative humidity of 65%,in accordance with ISO/R483-1966(E).
Characterization.The wide X-ray diffraction pat-terns (WXRDPs)were recorded with an X-ray diffrac-tometer (D/MAX-1200,Rigaku Denki,Japan)and with Cu K R radiation (λ)1.5405×10-10m)at 40kV and 30mA in the range of 2θ)6-40°.The degree of crystallinity ( c )was calculated according to a previously reported method.39Infrared (IR)spectra of the sheets on KBr disks were recorded with an FTIR 3000spec-trometer (Shimadzu Co.).The light transmittance of the sheets with a thickness of 0.35mm was measured in the wavelength range of 400-800nm by using an UV-160A Spectroscope (Shimadzu Co.)according to the Beer -Lambert law to give percent light transmittance.Sections of the sheets were studied with the aid of a scanning electron microscope (S-570SEM,Hitachi).The sheets were frozen in liquid nitrogen and then fractured and coated with gold prior to the SEM experiments.The differential scanning calorimetry (DSC)analysis of the samples was performed with a thermal analyzer (Per-kin-Elmer DSC-2C,Norwalk,CT)under nitrogen at-mosphere from -30to 150°C at a heating rate of 10°C/min.
Measurement of Mechanical Properties.The mechanical properties of the sheets were measured with a tensile tester (CMT6503,Shenzhen SANS Test Ma-chine Co.Ltd.,China)according to ISO6239-1986(E)with tensile speed 5mm/min to determine the tensile strength (σb )and breaking elongation ( b ).The sheets were immersed in water at room temperature for 1h and then the water resistance was measured.31The water resistance (R )of the sheets was evaluated from the σb(dry)value in the dry state and the σb(wet)value in the wet state by the following equation:
The water content (W H 2O ,wt %)in the sheets was measured according to ISO62-1980(E).W H 2O was calculated by applying the formula
where W w is the weight of the wet sheet and W d is the weight of the dry sheet.The moisture content (W mc ,wt %)was determined as described in ref 40and calculated
using
Figure 1.Sketch map of mold used.
R )σb(wet)/σb(dry)
(1)
W H 2O )[(W w -W d )/W d ]×100
(2)
W mc )[(W m -W d )/W d ]×100
(3)
Ind.Eng.Chem.Res.,Vol.40,No.2,2001559
where W m stands for the weight of the sheet stored at 75%RH for 1week and W d is the weight of the dry sheet.
Results and Discussion
Effects of WPU Content on Mechanical Proper-ties.The effects of the WPU content on the tensile strength (σb )and breaking elongation ( b )of the molded sheets are shown in Figure 2.The tensile strength of WPU was 23MPa and the breaking elongation was 520%.The tensile strengths of the sheets STPU15-STPU30were higher than those of both TPS and WPU,suggesting an interaction between starch and WPU.The breaking elongations of the STPU sheet were between those of starch and WPU and much higher than that of TPS.The results indicate that the mechanical properties of TPS improved remarkably by mixing with WPU using the heating-press method.The WPU plays an important role in improving the mechanical properties of the STPU sheets.
Effects of WPU Content on Water Resistance.Figure 3shows the effect of the WPU content (W WPU )on the water resistance (R )of the sheets.The water resistance of the STPU sheets increased considerably with increasing WPU content.The R value for the sheet TPS was 0.01,and that for STPU30was 0.24,24times that of the TPS.The latter value was attributed to the excellent water resistance of the WPU component.The effect of the WPU content (W WPU )on the absorbed water (W H 2O )is shown in Figure 4.The W H 2O value of the TPS sheet was about 317wt %,significantly higher than the corresponding values for the STPU sheets,which were 70%for STPU10,34%for STPU20,and 58%for STPU30.
This further supports our claim that mixing the TPS with WPU was beneficial in terms of improving its water resistance.
The effect of WPU content on moisture content of the STPU sheets is shown in Figure 5.With increasing WPU content,the moisture content of the STPU sheets exhibited a sharp drop,indicating that polyester-based WPU enhanced substantially the moisture-proofness of the STPU mixtures because of the low moisture content for WPU (0.1%).
Structure and Miscibility.The WXRD patterns of the TPS,STPU20,and WPU sheets are displayed in Figure 6.The degrees of crystallinity ( c )of TPS,STPU20,and WPU were 0.18,0.45,and 0.44,respec-tively.The TPS material was almost amorphous.The peaks at 19.5°and 13°in the TPS pattern are attributed to V-type crystallinity,formed after recrystallization of amylose after destructurization or plasticization of starch granules.22The result indicates that partially recrystallized starch formed in the sheet STPU.Three diffraction peaks of WPU at 2θ)13.8°,16.8°,and 21.4°are due to the orderly arrangement of soft segments,and a peak at 24.3°is from hard segments.36Interest-ingly,the peak at 16.8°for the STPU20sheet was higher than the peaks recorded for the other two samples.It has been reported that the B-type crystal-linity at 16.8°for TPS is attributed to recrystallization of both amylose and amylopectin.22The sharp peak at 16.8°for WPU resulted from the orderly arrangement of soft segments.36It is worth noting that the peak at 24.3°in the STPU20pattern disappeared,because of the interaction between the -COOH or -NH groups of WPU and the -OH groups of starch.Therefore,the TPS and WPU are miscible.However,in general,the crys-tallinity of the mixtures with good miscibility is
expected
Figure 2.Effect of WPU content (W WPU )on the tensile stress at break (σb )and breaking elongation ( b )of the STPU
sheets.
Figure 3.Effect of WPU content (W WPU )on the water resistance (R )of the STPU
sheets.
Figure 4.Effect of WPU content (W WPU )on the water content (W H 2O )of the STPU
sheets.
Figure 5.Moisture content for the STPU sheets as a function of WPU content.
560Ind.Eng.Chem.Res.,Vol.40,No.2,2001
to decrease;the recorded increase in c for the STPU20sheet in this case implies that the mixture had a certain level of miscibility and was not perfect on a molecular scale.
Figure 7displays some representative DSC thermo-grams of the TPS,STPU20,and WPU sheets.Their melting points and melting enthalpies are shown in Table 1.The T g of WPU usually was between -70and -40°C.41The T g of TPS containing 13.3%water content
was not obvious on the DSC curve.In addition,the ?C P of starch is very low.Both STPU20and WPU exhibited clear endothermic peaks,indicating that they both contained crystalline or semicrystalline material.How-ever,the intensity and position of the peaks for the STPU20sheet were lower than those for WPU,sug-gesting miscibility.On the contary,TPS behaved rather as an amorphous material almost without any crystal melting peak.Two small peaks for STPU20might indicate a crystallization melting of WPU and a recrys-tallization -melting process for a new crystal peak of the partially recrystallized starch.The melting enthalpy of STPU20was much lower than that of WPU,resulting from the partial crystallinity of WPU being
destroyed
Figure 6.X-ray diffractograms of the TPS,STPU20,and WPU
sheets.
Figure 7.DSC thermograms of the TPS,STPU20,and WPU sheets.
Table 1.Experimental Results of DSC for the TPS,STPU,and WPU Sheets
melted crystallinity peak (°C)material onset point midpoint endpoint melting enthalpy (J/g)STPU2034(336(146(40.71(0.3PU
35(3
40(2
48(2
4.46(
0.6
Figure 8.IR spectra of the sheets of TPS,STPU20,an uncom-pressed mixture of TPS and WPU,and
WPU.
Figure 9.Effect of WPU content (W WPU )on the light transmit-tance of the sheets at 600nm.
Ind.Eng.Chem.Res.,Vol.40,No.2,2001561
(see Figure 6),and the melting enthalpy of the recrys-tallized starch in STPU20is very low.These results support the conclusion from the WAXDPs.
The IR spectra of sheets of TPS,STPU20,a mixture of TPS and WPU (80:20),and WPU are shown in Figure 8.The absorption of the carboxylic groups of WPU at 1225cm -1significantly decreased in the IR spectra of STPU10-STPU30,indicating that there is an interac-tion between the carboxylic groups of WPU and the hydroxyl groups of TPS.The band at around 1736cm -1is attributed to the stretching of free urethane carbonyl groups,whereas the band at 1726cm -1is assigned to hydrogen-bonded urethane carbonyl groups.42,43Com-pared with the uncompressed mixture,the native intensity of the peak for STPU20at 1726cm -1in-creased.This indicated that some of the free-urethane carbonyl groups of the polyurethane had bonded with hydrogen groups of the starch,suggesting that an intermolecular force occurred between polyurethane and starch in the STPU.The structure analysis is in good agreement with the results from mechanical properties,the WXRDPs,and DSC.Therefore,the WPU plays an important role in forming of a new morphology and enhanceming the mechanical properties of the STPU.Figure 9shows the light transmittance of the STPU sheets as a function of WPU content.Molded starch TPS exhibited higher light transmittance (95%)than the STPU and the cast starch film prepared and measured before (63%).The light transmittance of STPU5-
STPU30reached approximately 86%,similar to that of WPU (88%).The results imply that the granular struc-ture of the starch has been utterly deformed or de-stroyed and a continuous polymeric phase has been formed,which led to the enhanced light transmittance of the STPU.Otherwise,the light transmittance should be more lower due to recrystallization of starch.There-fore,the starch and WPU in the mixtures are miscible.Figure 10shows SEM images of the sections of the sheets of TPS,STPU20,STPU30,and WPU.The SEM images of all of the samples indicated a homogeneous structure for the sections.For TPS,this is due to high pressure and temperature,resulting in all of the gran-ules of the starch being broken up and formed into a homogeneous phase.The section of WPU was slightly coarse because of microphase segregation between hard and soft segments.The sheets STPU20(B)and STPU30(C)were characterized by homogeneous morphology containing TPS and WPU,an assumption supported by the light transmittance experiments shown in Figure 9,which suggest a miscibility between starch and waterborne polyurethane.Conclusions
Compression-molded sheets based on mixtures of polyester-based WPU and thermoplastic starch (TPS)were successfully prepared.When the WPU content was in the range of 5-30wt %,both the tensile
strength
Figure 10.SEM images of sections of (A)TPS,(B)STPU20,(C)STPU30,and (D)PU.
562Ind.Eng.Chem.Res.,Vol.40,No.2,2001
and the breaking elongation of the STPU sheets were higher than those of TPS.The water resistance,moisture-proofness,and breaking elongation of the mixtures significantly increased with an increase in the WPU content.The IR,WXRDP,DSC,and SEM analyses of the prepared samples indicated that interactions be-tween TPS and WPU exist in the STPU sheets,resulting in a certain level of miscibility.The WPU played an important role in improving the mechanical properties and water resistance and enhancing the miscibility. Acknowledgment
This work was supported by the National Natural Science Foundation of China(59773026and59933070) and the Laboratory of Cellulose and Liginocellulosic Chemistry of the Chinese Academy of Science. Literature Cited
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Received for review June15,2000 Revised manuscript received September19,2000
Accepted October17,2000
IE000582T
564Ind.Eng.Chem.Res.,Vol.40,No.2,2001
雅思口语素材汇总之端午节 雅思口语素材:Dragon Boat Festival(端午节) Qu Yuan The Dragon Boat Festival, also called the Duanwu Festival, is celebrated on the fifth day of the fifth month according to the Chinese calendar. For thousands of years, the festival has been marked by eating zong zi (glutinous rice(糯米)wrapped to form a pyramid using bamboo or reed leaves) and racing dragon boats. The festival is best known for its dragon-boat races, especially in the southern provinces where there are many rivers and lakes. This regatta(赛舟会)commemorates the death of Qu Yuan , an honest minister who is said to have committed suicide by drowning himself in a river. Qu was a minister of the State of Chu situated in present-day Hunan and Hubei provinces, during the Warring States Period (475-221BC)(战国时期). He was upright, loyal and highly esteemed for his wise counsel that brought peace and prosperity to the state. However, when a dishonest and corrupt prince vilified Qu, he was disgraced and dismissed from office. Realizing that the country was now in the hands of evil and corrupt officials, Qu grabbed a large stone and leapt into the Miluo River on the fifth day of the fifth month. Nearby fishermen rushed over to try and save him but were unable to even recover his body. Thereafter, the state declined and was eventually conquered by the State of Qin. The people of Chu who mourned the death of Qu threw rice into the river to feed his ghost every year on the fifth day of the fifth month. But one year, the spirit of Qu appeared and told the mourners that a huge reptile(爬行动物)in the river had stolen the rice. The spirit then advised them to wrap the rice in silk and bind it with five different-colored threads before tossing it into the river. During the Duanwu Festival, a glutinous rice pudding called zong zi is eaten to symbolize the rice offerings to Qu. Ingredients such as beans, lotus seeds(莲子), chestnuts(栗子), pork fat and the golden yolk of a salted duck egg are often
全国翻译价格 关于全国各地区翻译价格我们根据客户的不同需求和具体情况，提供多种等级和特色的翻译服务，供客户选择：（注：以下报价均为参考价格，精确报价将根据稿件内容的难度、技术处理的复杂程度和时限要求的缓急而定。
品质控制 坚持高端定位是外语通翻译的核心要素，追求高品质翻译需要译员具备深厚的语言功底和专业背景知 识，更需要严格的质量控制体系来管理这一过程： 外语通六阶梯质量控制体系 第一阶梯：译文评估承接 分析稿件性质、用途要求、商务背景、专业术语、数量和交稿时间等，确定是否有100%的把握承接， 否则坚决放弃，以免因质量或交稿时间耽误客户和影响品牌形象。 第二阶梯：专业译员翻译 专业背景的译员只专注于一个行业领域的精准翻译，项目经理根据译文评估，从外语通全球译员库中 分析挑选多名此行业的专业译员成立项目组，统一专业术语和标准，协同翻译。 第三阶梯：翻译质量监控 项目经理监控翻译进展，每日集中疑难词汇，请签约专家释疑。每日抽查译文质量，及时解决译文质 量问题。 第四阶梯：译文校对排版 汇总所有译文，查错补漏，进一步统一术语，按原文进行排版，形成完整初稿。 第五阶梯：专家译审修改 专家译审对翻译初稿进行翻译准确性审核，确保译稿忠于原文，专业词汇纯正地道。 六阶梯：外籍母语润色第 在华外籍翻译（外译中稿件由中文功底深厚的编辑）对译稿的语法、词汇进行修正和润色，确保译稿 纯正、地道，达到母语品质。 外语通翻译严格执行《ISO译文质量体系》，《翻译质量国家标准GB/T 19682-2005》： 译文质量标准Ⅲ类通用笔译Ⅱ类专业笔译Ⅰ类高级笔译译文用途内容概要、参考资料一般文件和材料正式文件、法律文书、出版物错漏译率小于5‰小于2‰0‰ 译员经验3年以上5年以上8年以上 译员学历硕士以上硕士以上硕士以上 行业背景常识业内资深 海外背景无/短期中期长期 译文校对有有有 专家译审无有有 母语润色无无有 译文排版简单排版详细排版出版级别
口语常用背诵素材 一，喜好和厌恶： 1.（释放压力）I guess most young people enjoy listening to music. It’s a perfect way to reduce stress/relieve stress. (*It’s a perfect stress-buster.) 2.（休闲）I think the best way to relax and kill time (kick back and relax) is to be with friends. Chatting with them helps me unwind/wind down (* Chatting with them is very therapeutic). 3.（放松）I found it pretty relaxing to flick through a magazine before going to bed (*before hitting the sack/hitting the hay). 4.（运动）Jogging on sunny days and simply basking in the sun(bathing in the sun) is super enjoyable(pleasurable). /Jogging is my favorite workout. It can always cheer me up after I’ve been down and depressed. And it can help me shed some unwanted weight. 5.（喜欢，提升心情）I’m quite into watching sitcom (I’m fascinated by, I’m crazy about, I adore, I’m very fond of...). Spending 20 minutes in front of the screen and having a good laugh after dinner really puts me in a better mood/ switch my mood/ lift my spirits. 6.（天气）I fancy spring most compared to the other three. Summer is simply too hot and stuffy (*muggy), and you can’t stay out for two minutes without getting sweaty and smelly. Autumn is too dry and winter too freezing cold. 7.（电影）I’m a movie buff (Movies are my biggest pastime), and I would either catch one on my couch or go to the movie theatre when they have the one I like on the big screen./ It's a great form of relaxation for me to while away the hours of a long flight, to keep my family together on the sofa, and to give me a bit of a thrill. 8.（无聊困难）I’m terrible at what I study now./(History is never my forte/ my strong suit). The classes are kind of a drag (It’s super dull/ *It’s mind-numbing), and there’s always loads of (tons of) homework to do. Memorizing those facts and years is a lot of effort (is tricky; is no picnic; is challenging for me). 9.（不能忍）I can’t stand (I hate, I totally dislike) the busy traffic in my city. I’m sick and tired of always getting stuck in traffic for a long time during rush hours. It really bothers me (It drives me crazy, *It drives me up the wall). 10. （受欢迎）Hip-hop is really trendy (is catching on, is all the rage) among young people these days. 二，时间和地点 11. （优点）What’s great about my home town is that there are plenty of shopping malls, coz I’m a shopaholic and I can shop for hours. 12. （远）The stadium is quite far away from where I live, and every time I want to do there, it takes me roughly 40 minutes by bus to arrive. (It’s one-hour drive from the city center.) 13. （方便）My apartment is in the center/heart of the city, a handy location where I can find supermarkets and clubs right on my doorstep. It’s a bit noisy though. 14. （近）I’m a movie-goer and and there’s a movie theater pretty close to my home, so I go there quite often (frequently). (close to my home= *within walking distance of my home , *in close proximity to my home) 15. （经常）I have a heavy workload at school, so I have to go to the library to study pretty much
雅思口语素材 Document serial number【LGGKGB-LGG98YT-LGGT8CB-LGUT-
Useful Expressions: Words and phrases Friends and communication: solidify/ strengthen/ enhance/ promote communication / connection with mutual understanding relationship network/circle of f r i e n d s cultivate/develop friendship with s b . keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality
expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive competence accumulate experiences learn lessons from past experiences Work and experience the scarcity of employment o p p o r t u n i t i lay the foundations for career p r o s p e r i t y
U s e f u l E x p r e s s i o n s: Words and phrases Friends and communication: mutual understanding solidify/ strengthen/ enhance/ promote communication / connection with relationship network/circle of friends cultivate/develop friendship with sb. keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive accumulate experiences competence learn lessons from past experiences Work and experience the scarcity of employment opportunities lay the foundations for career prosperity immerse oneself in endless job tasks boost/augment/enhance efficiency be adept in boost one’s c ompetitiveness Health and pressure diminish individuals' leisure time drive away lassitude lighten one’s burden homework/workforce overload
翻译公司收费标准 1.客户需要翻译的目标语言的普遍性和稀缺性可能导致非常 不同的费用。英语比较普遍，需求大，市场专业的英语翻译人 才也很多，翻译公司无论是从降价到抢占市场，还是成本核算 来考虑，英语收费都比较合理和透明。 其他诸如法语、德语、日语、俄语排在第二梯队，翻译公司收 费标准一般都是200-280元，视稿件专业度和数量略有调整； 意大利，西班牙，越南，泰文等东南亚语种已经接近稀有语 种了，翻译报价至少300元千字起。 2.根据翻译项目类型 常见的翻译方法主要包括翻译翻译、同声传译、本地翻译、口译翻译等，翻译项目自然是不同的收费。 3.根据翻译项目时长 这一时期的持续时间主要是指项目长度：同声传译、会议翻译、商务洽谈、双语主持人、口译、护送翻译、展览翻译，当然，视频翻译、音频翻译按时间计算的时间和会议类型是一个重要因素，是翻译时间决定翻译价格的一个重要因素。 4.根据翻译项目字数
翻译项目的字数是影响收费的重要因素之一，翻译字数主要对于笔译而言，例如：文件翻译、图书翻译、资料翻译、画册翻译等等，这些文件资料的字数决定了项目的翻译价格和翻译收费标准。 5.根据翻译项目语种 主流语种：英语、日语、韩语等和小语种：阿拉伯语、希腊语、印尼语等的翻译收费标准区别。我们知道：“物以稀为贵，”所以小语种的翻译报价会比主流语种收费要高的。 6.根据翻译项目难易程度 对于翻译公司来说，翻译费在很大程度上取决于翻译的难度程度，不同的行业术语不同，难度不同; 专业翻译公司将根据翻译人员的翻译水平、专业知识、翻译经验等方式来评价自己的翻译团队，高层次的翻译人员当然都是高收费; 如通用翻译、精细翻译、出版层次等不同类型的翻译报价不同，稿件的行业领域、材料难度、选择翻译类型等都是决定翻译公司收费标准的因素。
近期雅思口语卡片新题素材汇总 人物Describe a classmate of yours Describe a good friend Describe a happy person Describe a colleague Describe a neighbor Describe your own personality Describe a family member Describe a child you know Describe an old person Describe an old person who has influenced you the most Describe a successful person Describe a singer Describe a sportsman Describe a movie star Describe a character in TV or movie Describe a teacher of yours Describe a famous person that you want to spend a day with.地点Describe a building at schools Describe a historical place
Describe a monument Describe an interesting building Describe a lake, river or sea. Describe a peaceful place Describe a leisure place Describe a park Describe a place of interest Describe a natural beauty Describe a city you want to live in Describe a place you have visited Describe a place you always go for shopping
英文合同翻译价格英文合同翻译需要多少钱 在企业的经营过程中，有时候可能会涉及到翻译这个问题，但是一般的小企业并没有专门的人去做这件事情，大部分都是外包。那么对于企业来讲，翻译一份英文合同需要多少钱呢？作为浙江省最大的翻译公司，以琳翻译就在这里为大家解读一下。 一般来讲，翻译这项服务都是以字数来计价的，市场上的一般的价格是50-80元/千字，这是一个基本的价格。但是不同的公司的专业性质不一样的话，所给出的价格也是不一样的。对于公司的衡量标准来讲，影响价格的因素主要有：公司的资历、翻译人员的专业性、翻译文件的种类、难度等。所以，如果你需要去找翻译公司去服务，那么就需要考虑这些方面的东西。而对于合同这种文件，对于公司来讲是十分重要的，所以也需要去找专业的公司去进行翻译，如果是找一个资质不够的公司或者团队，那么就可能产生一些意想不到的问题，从而影响到公司的最终利益。 下面，我们来看看以琳翻译给出的翻译的价格。 从上面的价格可以看出，以琳翻译给出的价格是高于一般市场上的价格的，最低级别的翻译是160元/千字，然后分为A、B、C三级。C级译稿为普通中籍译员+中籍译员审核，满足客户对译文的普通要求。这是对于一般的合同而言的，但是如果是部分专业性质较强或者要求比较高的译文的话，那么可以选择更高级别的翻译，当然价格还是相对比较高的。 那么以琳翻译的资质是怎么样呢？我们再来看一下。 杭州以琳翻译有限公司是浙江省最大的实体翻译公司、中国翻译协会单位会员、美国翻译协会会员、全国翻译专业硕士研究生教育实习基地、西博会指定合作伙伴、以琳杭州翻译公司翻译团队成员均具有五年以上专业翻译、项目管理经验，绝大部分成员具有十年以上行业翻译经验。翻译服务涵盖英语、法语、韩语、日语、德语、俄语、西班牙语、葡萄牙语、
一.雅思P2相关话题 一日假期 和外国朋友一起吃饺子的建议 1.The best way to eat a dumpling is in one bite. “Dumplings are designed to be consumed in one mouthful, as it’s the best way to enjoy the combination of the meat filling and the very thin and springy flour wrapper,” If you can’t use chopsticks, eat your dumplings with your fingers. Avoid using a fork at all costs, as piercing the dumpling will compromise the flavour. 3.Mix two parts vinegar with one part soy sauce for the perfect dumpling sauce. Add young ginger slices too， Chili oil is also a great addition when available. 4.Dumplings are just one element of dim sum. “Dim sum doesn’t just include dumplings. It’s also braised dishes like pork ribs, chicken feet, and beef balls. It’s actually small tapas-style dishes that are eaten in Cantonese restaurants at lunchtime,” 5.Xiao long bao dumplings are different from others as they contain broth. They originated in the Jiangnan region of China and are prepared in bamboo steaming baskets called xiao long, hence the name. 6.When eating xiao long bao or a dumpling with a ~soupy~ interior, opt for chopsticks and a spoon. “As soon as the dumplings arrive at your table, lift one from the steamer basket onto a soup spoon. Next, tear the skin of the dumpling by pressing the chopsticks from the side of the dumpling onto the spoon. The broth will ooze out onto the spoon. Sip the soup then enjoy the dumpling in one mouthful.” 7.You can tell whether your dumpling was cooked fresh or frozen by looking at the skin. “The skin of a freshly made dumpling is springy and light. “Frozen ones tend to be soggy.” 8.When makingdumplingsat home, try to keep your packages small.
精诚英语翻译报价50-80元千字（市场价格100左右 精诚英语翻译工作室是由众多英语方面精英组成的翻译团队,一直致力于为广大中小企业和个人提供专业低价中英文翻译服务。价格是我们永远的优势！！！！最低价格支付宝担保交易，让你省钱又放心接受试译！！自信源于专业可以百度搜索精诚英语翻译找到我们 选择我们的理由：可以百度搜索精诚英语翻译找到我们 1.保证价格最低，团队网络化运作，无需经营成本，可以通过低价让利于客户。（有些客户看到这么低的价格还不敢相信，但是对于我们来说是完全可以接受的。） 2.保证准时、保密、准确 3.接受淘宝交易，让您没有任何担忧。 4.长期翻译经验，保证质量让您满意。 龚如心遗产案虽然告一段落，「遗产」二字仍然成为近日香港的焦点。新春期间，民政事务局局长曾德成表示，政府将展开全港非物质文化遗产首期普查，希望市民为遗产清单提出建议。 「遗产」是「资产」？ 近五、六年间，香港对保护本地小区和文化传统的意识高涨，现在政府带头要列一个「非物质文化遗产」清单，理应是很受欢迎之举。不过普查尚未展开，就引来学者争议，其中单是「非物质文化遗产」这个译名，就引起不少误会。 「非物质文化遗产」的原文是intangible cultural heritage（英文）或patrimoine culturel immateriel （法文），是联合国在1997年以尊重多元文化为大原则而提出的概念，并由联合国教科文组织制定「保护非物质文化遗产公约」，2006年生效。 「非物质文化遗产」是中国大陆的翻译，香港有学者不约而同就「非物质」和「遗产」二字提出质疑。香港城市大学中国文化中心主任郑培凯早在2005年就大声疾呼译名不妥。他认为原文heritage/patrimoine的意义是「传承」而非资产，不容易引发出财产的概念。而现在约定俗成译作「遗产」，容易令人觉得祖宗留下的东西，是可以变卖和投资的生财工具，与联合国提出的文化传承精神背道而驰。郑教授认识，正确的译名是「非物质文化承继」或「非实物文化传承」。另一位民俗学研究者陈云进一步指出，intangible「乃触摸不到的事，无形无相之事」，应用「精神价值」代之，「非物质」有消灭了精神之嫌，所以中国人应堂堂正正将之翻译为「无形文化传承」。 姗姗来迟的「遗产」 不论是「非物质」还是「无形」，「遗产」还是「承传」，即使公约成员国中国曲译甚至错译，香港特区政府还是只能照单全收。而且，随之而来的不止是字面的斟酌，而是「遗产」的搜寻和管理问题。 中国自2005年起，就开始非物质文化遗产（由于这个名称已约定俗成，故下文仍沿用之，并简称为「非遗」）普查，并陆续列出清单。香港也在翌年提出编制非遗清单，但却延至去年才聘专家普查，估计最快要2012年才完成。 非遗普查尚未展开，在国家文化部的再三邀请（或是说催促？）下，去年九月，香港终于申请将长洲太平清醮、大澳端午游涌、大坑舞火龙和香港潮人盂兰胜会列为第三批国家级非遗，预计今年六月有结果。 其实香港已错过了2006和2008年首批和第二批的申报机会，所以，至目前为止，在中国的文化版图上，香港是唯一没有任何有形和无形「遗产」的主要城市／特区，就连比邻的澳门也凭神像雕刻工艺获得2008年国家级非遗之「奖项」。 有人说非遗不过是人有我有，纯粹锦上添花；也有人说，中国在维护主权和领土完整的概念下，又怎能在文化层面少了香港一席？香港能够「出产」一个非遗，中国在全球的文化图谱中就多一个筹码。 姑勿论背后原因为何，由于「保护非物质文化遗产公约」也适用于香港，香港特区政府就有责任找出和保护濒危失传、与社会关系密切及具香港独特性的文化传统。现在起步虽迟，但为时未晚。 「遗产」的管理问题 不过，既然政府要展开普查，另一个问题来了。民间传统应该是属于民间的，并由民间自行发展，还是属于官方，由政府承担保护与管理？ 据政府委聘负责首期普查的香港科技大学华南研究中心主任廖迪生表示，政府至今仍未有任何政策配合或承诺给予全面的保护，所以，即使清单出炉，有些遗产仍有可能难逃「破产」的命运。他强调制作非遗清单只是第一步，更重要的是如何保护这些项目。 再问民政事务局，曾德成局长除了曾向立法会议员表示，制定清单是向国家文化部申请列为国家级非遗的第一步，进而再向联合国教科文组织提出申报为世界非物质文化遗产，他所提出的，就是以遗产作招徕吸引外地游客，「以提升香港作为旅游目的地的吸引力」。 这才是令人担心的地方。「非遗」这个金漆招牌在中国许多地方都有点石成金之效。戴上这个冠冕，民俗文化很容易沦为生财工具、游客的消费品，连婚嫁仪式也可用来表演，完全违背了保护非遗的原意。曾德成之言，是否意味着香港也要跟着祖国一起走上同一条路？
雅思口语素材训练 by Tina Li Do you like music??A—肯定:Definitely yes, everyone enjoys music, and I am no exception! I love... 否定 :Well, honestly speaking, music is really not my cup of tea, simply because... ( 给出直接原因) What—pop, techno ( 电音音乐), hip-hop, rock, meditation ( 冥想乐) and especially light music.( 罗列名词) Where—Normally speaking, I would like to listen to music with my earphones when I take a ride on public transportation. ( 给出一个具体的场景) When—As long as I couldn’t go to sleep, I’d like to listen to some light music to calm myself down. ( 给出一个条件 :As long as I..., I would...)
Who—My most favourite singers include Adele, James Blunt, Avril Lavigne, and so forth. ( 喜欢的歌手) Why—I am fond of music mainly because it can cheer me up greatly when I feel down/low/ blue/bored/tired/depressed. ( 心情不好的时候让我高兴起来)?Besides, I also believe that music is an indispensable part of culture and tradition, through which I could have a better understanding of different cultures around the world, including cowboy culture, African-American street culture, the three main reli- gions and so on. ( 有助于理解不同的文化) Do you like watching movies?? A—Speaking of movies, yes, I am a big fan of all types of movies, such as...?What—comedy, action, romance, sci-fi, manga, vampire, zombie, animation...
英文翻译价格 根据以英文作为母语的人数计算，英文是最多国家使用的官方语言，英语也是世界上最广泛的第二语言，也是欧盟，最多国际组织和英联邦国家的官方语言之一。但仅拥有世界第二位的母语使用者，少于标准汉语。上两个世纪英国和美国在文化、经济、军事、政治和科学上的领先地位使得英语成为一种国际语言。如今，许多国际场合都使用英语做为沟通媒介。英语也是与电脑联系最密切的语言，大多数编程语言都与英语有联系，而且随着网络的使用，使英文的使用更普及。英语是联合国的工作语言之一。 为了方便大家了解英文翻译价格，小编在目前汇集最多翻译团队的高校译云上面获得了不同翻译精英团队所展示的价格。 暨南大学翻译中心：中英---普稿---150---千字英中---普稿---250---千字 武汉理工大学-外国语学院MTI翻译中心 ：中英互译中英130-150 英中100-130 华中科技大学-翻译研究中心 ：中英互译中英120-150 英中100-120 湖南科技大学MTI中心：中英---普稿---150---千字 上海师大外国语学院翻译中心： 中英---普稿---200元---千字英语普通文本译成汉语---120元---千字西南大学翻译中心：中英---普稿----300---千字英中---普稿---200---千字 上海理工大学MTI翻译中心：中英---普稿---100---千字 南京财经大学外国语学院翻译研究中心：中英---普稿---100---千字 一般英文翻译价格是是在100—300元每千字，根据译员质量、翻译内容、需要的时间等都会有一定的波动，所以以上价格供大家参考，具体的可以准备好稿件了去问，这样会更加准确一些。
做有偿工作的人 Describe a person you know who is doing a paid job. You should say: Who this person is What job it is; How long the job lasted; And explain why you or this person chose to do this job. 让你笑的小孩 Describe a time that a child did something that made you laugh. You should say: When this happened Who the child was What the child did And explain why it was funny 特殊的旅行 Describe an educational trip you went on when you were in school. You should say: When and where you went; Who you went with; What you did; And explain what you learned on this trip.
Describe an electronic machine you want to buy. You should say: What it is When you know this machine What specific And explain why you want this machine 难忘的广告 Describe an unforgettable advertisement (that you saw or heard liked) You should say: Where you saw or heard it What kind of advertisement it was What the contents of the advertisement were (or, what product or service was advertised) And explain how you felt when you saw or heard this advertisement/why you like it
【2019-2020】雅思口语话题素材-精选word文档 本文部分内容来自网络整理，本司不为其真实性负责，如有异议或侵权请及时联系，本司将立即删除！ == 本文为word格式，下载后可方便编辑和修改！ == 雅思口语话题素材 雅思口语素材总结雅思口语要求学生平时多多的积累素材，在口语方面要不断的加强练习。烤鸭们要多模拟不同的场景，多用丰富的口语短语，这 样你的雅思口语水平才能越来越高。下面是常用的一些口语短语，供大家参考！ 1、 a change of pace 改变步调;换口味 You cant do these chemistry experiments all day long . You certainly need a change of pace . 2、 a far cry from 相距甚远 The published book is a far cry from the early manuscript . 3、 and how 的确 A ： Shes a good dancer . B ： And how . 4、 a matter of time 时间问题 It is only a matter of time . 5、 a phone call away 一个电话之远，即愿意过来帮忙 If you need my help , do let me know . Just remember I am a phone call away . 6、 a while back 不久以前 Well , I listened to that CD you lent me a while back . 7、 all along 一直 I knew it all along . 8、 anything but 绝对不 I was anything but happy about going . 9、 account for 解释 How do you account for it ? 10、 after all 毕竟;终究 A ： Ive just seen the X - rays and your teeth look just fine . B ： I see . Then there is nothing to worry about after all . 11、allergic to 对过敏 Oh man ! Something in this room is making my eyes itch . I must be allergic to something . 12、 at sbs service 愿为某人服务 I am at your service at any time . 13、 around the clock 24小时不停 Martha studied around the clock for management exam . 14、 as far as I know 就我所知 But as far as I know , he once won the world champion at the Olympic Games . 15、 at home with 对很熟悉 She is at home with problems like this . 16、 back out 退出 A ： Wasnt Bert supposed to sing tonight ? B ： Yes , but he backed out at last minute . 17、be cut out for 适合于，有做某事物的天赋 She is cut out for a dancer . 18、 be absorbed in 全神贯注于某事物 She has been absorbed in a horrorfiction . I cant tear her away . 19、 be addicted to 对某事物上瘾 She has been addicted to drugs for years . 20、 be attached to 对某事物有感情 A ： Im amazed that you are still driving that old car of yours . I thought you would have gotten rid of it years ago . B ： It runs well and Ive actually been quite attached to it .