the formation of prenucleation clusters with dimen-sions of 0.6to 1.1nm (step 0).In analogy to the chemistry of calcium phosphate (31),we consider them to be the smallest stable agglomerates of CaCO 3present from the beginning of the reaction.Aggregation of these clusters in solution leads to the nucleation of ACC nanoparticles with a size distri-bution centered around 30nm (step 1).Association of these particles with the template surface initiates the growth of ACC (step 2),using the nanoparticles in their neighborhood as feedstock.Next,randomly oriented nanocrystalline domains are formed inside the otherwise amorphous particles (steps 3and 4).On the basis of the model of Zhang et al .(23),we expect these domains to be unstable and in equi-librium with the amorphous phase.In the last steps,the orientation that is stabilized through the inter-action with the monolayer becomes dominant (step 5)and develops into a single crystal (step 6).This single crystal probably grows by the further addition and incorporation of ions and clusters from solution.The initial experiments of Mann and co-workers showed that the present system could produce cal-cite (11.0)or vaterite (00.1)depending on the pre-cise conditions (16,32).Later,it was demonstrated that rapid CO 2evaporation favors the kinetic product,vaterite (21,22),whereas lower evaporation rates lead to the calcitic form (21).These results are confirmed by our finding of (00.1)oriented vaterite in the present work (i.e.,in a fast-outgassing thin film)and the formation of (11.0)oriented calcite in crystallization dishes (fig.S7)(15)from which CO 2outgassing is slower.Moreover,the observation of randomly oriented vaterite crystals also puts in perspective the synchrotron x-ray scattering exper-iments that showed the formation of randomly oriented crystals from the same system (22).
The nanoscopic prenucleation clusters that we visualized are the smallest stable form of CaCO 3and are likely the building blocks of the amorphous precursor particles observed in biomineralization;such particles are also observed in many synthetic systems and are not restricted to calcium carbonate (13,31).As a consequence of their aggregation,ACC nucleates in solution and subsequently assembles at the template.There,it is present as a temporarily stabilized but transient phase that mediates the trans-fer of information from the template to the mineral phase.This occurs through the selective stabiliza-tion of only one of the orientations present,leading to the development of a single crystal.
References and Notes
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3.B.L.Smith et al .,Nature 399,761(1999).
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Soc.London Ser.B 264,461(1997).
11.B.P.Pichon,P.H.H.Bomans,P.M.Frederik,
N.A.J.M.Sommerdijk,J.Am.Chem.Soc.130,4034(2008).12.J.R.I.Lee et al .,J.Am.Chem.Soc.129,10370(2007).13.D.Gebauer,A.V?lkel,H.C?lfen,Science 322,1819(2008).14.C.L.Freeman,J.H.Harding,D.M.Duffy,Langmuir 24,
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15.See supporting material on Science Online.
16.S.Mann,B.R.Heywood,S.Rajam,J.D.Birchall,Nature
334,692(1988).
17.S.Nickell,C.Kofler,A.P.Leis,W.Baumeister,Nat.Rev.
Mol.Cell Biol.7,225(2006).
18.The sedimentation coefficient s is defined as the velocity
v t of the particle per unit gravitational acceleration
(centrifugal acceleration:w 2r ,where w is angular velocity and r is the radial distance to the rotation axis).19.F.M.Michel et al .,Chem.Mater.20,4720(2008).20.D.Quigley,P.M.Rodger,J.Chem.Phys.128,221101(2008).21.E.Loste,E.Diaz-Marti,A.Zarbakhsh,F.C.Meldrum,
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23.T.H.Zhang,X.Y.Liu,J.Am.Chem.Soc.129,13520(2007).24.Y.Politi et al .,Adv.Funct.Mater.16,1289(2006)https://www.doczj.com/doc/3c6678403.html,m,J.M.Charnock,A.Lennie,F.C.Meldrum,
CrystEngComm 9,1226(2007).
26.J.Aizenberg,D.A.Muller,J.L.Grazul,D.R.Hamann,
Science 299,1205(2003).
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N.A.J.M.Sommerdijk,Chem.Eur.J.8,2561(2002).31.A.S.Posner,F.Betts,Acc.Chem.Res.8,273(1975).32.S.Rajam et al .,J.Chem.Soc.Faraday Trans.87,727(1991).33.Supported by the European Community (project code
NMP4-CT-2006-033277)and the Netherlands
Organization for Scientific Research (NWO).We thank A.V?lkel and H.C?lfen for performing and evaluating the ultracentrifugation measurements;D.Gebauer and A.Verch for time-dependent solution composition determination of the mineralization solutions;
F.L.Boogaard,E.J.Creusen,J.J.van Roosmalen,and P.Moeskops for their contribution to the 3D
reconstructions of the tomograms;and P.T.K.Chin for providing the CdSe nanorods.
Supporting Online Material
https://www.doczj.com/doc/3c6678403.html,/cgi/content/full/323/5920/1455/DC1Materials and Methods SOM Text Table S1
Figs.S1to S7
5December 2008;accepted 30January 200910.1126/science.1169434
Self-Repairing Oxetane-Substituted Chitosan Polyurethane Networks
Biswajit Ghosh and Marek W.Urban *
Polyurethanes have many properties that qualify them as high-performance polymeric materials,but they still suffer from mechanical damage.We report the development of polyurethane networks that exhibit self-repairing characteristics upon exposure to ultraviolet light.The network consists of an oxetane-substituted chitosan precursor incorporated into a two-component polyurethane.Upon mechanical damage of the network,four-member oxetane rings open to create two reactive ends.When exposed to ultraviolet light,chitosan chain scission occurs,which forms crosslinks with the reactive oxetane ends,thus repairing the network.These materials are capable of repairing themselves in less than an hour and can be used in many coatings applications,ranging from transportation to packaging or fashion and biomedical industries.
W
hen a hard or sharp object hits a ve-hicle,it is likely that it will leave a scratch,and for this reason the auto-motive industry looks for coatings with high scratch resistance.Because of their hardness and elasticity,polyurethanes exhibit good scratch re-sistance but can still suffer from mechanical dam-age.An ideal automotive coating would mend itself while a vehicle is driven.To heal mechan-ical damage in plants,suberin,tannins,phenols,or nitric oxide are activated to prevent further lesions (1–3),whereas in a human skin,the outer flow of blood cells is arrested by the crosslink network of fibrin,giving rise to wound-healing (4,5).Concentration gradients or stratification in living organisms inspired the development of spa-tially heterogeneous remendable polymers (6,7),composites containing micro-encapsulated spheres
(8–11),encapsulated fibers (12–14),reversible cross-linking (15,16),and microvascular networks (17).One example is epoxy matrices containing a glass hollow fiber filled with a monomer and an initiator with the “bleeding ”ability to heal poly-mer networks during crack formation (12).A sim-ilar phenomenon was used in another approach,in which a micro-encapsulated dicyclopentadiene monomer was introduced in a catalyst-embedded polymer matrix,which healed the crack near the ring opening of the monomer (8–11).Reversibil-ity of Diels-Alder reactions resulted in another approach to thermally repair damaged areas,and approach using malemide-furan adducts (15,16).Mimicking of microvascular structures (17),water-responsive expandable gels (7),and formation of supramolecular assemblies (18)are other ave-nues of remendability.
This study departs from previous approaches and reports the development of heterogeneous
School of Polymers and High Performance Materials,Shelby F.Thames Polymer Science Research Center,The University of Southern Mississippi,Hattiesburg,MS 39406,USA.*To whom correspondence should be addressed.E-mail:marek.urban@https://www.doczj.com/doc/3c6678403.html,
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polyurethane (PUR)networks based on oxetane-substituted derivative of chitosan (OXE-CHI),which upon reaction with hexamethylene diiso-cyante (HDI)and polyethylene glycol (PEG)(19)form heterogeneous OXE-CHI-PUR net-works.The choice of these components was driven by their ability to serve specific functions;PUR networks provide desirable heterogeneity through polyurethane and polyurea components,and OXE-CHI provides the cleavage of a con-strained four-membered ring (OXE)and ultra-violet (UV)sensitivity through CHI,the latter being a product of deacetylation of chitin,which is the structural element of exoskeletons of crus-taceans (e.g.,crabs and shrimp)occurring in abun-dance in nature.Figure 1illustrates a two-step reaction sequence leading to the OXE-CHI-PUR formation (20).The first step in this investigation was the synthesis of OXE-CHI,in which the pri-mary alcohol of CHI was reacted with chloro-methyl of OXE (21).An OXE ring was reacted to the C 6position of the chitosan molecule,which is confirmed by infrared (IR),Raman,and 13C-NMR (nuclear magnetic resonance)spectroscopy (20)(figs.S1,S2,and S3,respectively).The second step illustrates the reactions leading to the in-corporation of OXE-CHI into trifunctional HDI in the presence of PEG (1:1.4and 1:1.33molar ratios),confirmed by IR and 13C-NMR spectros-copy (20)(figs.S4and S5,respectively).
Networks were allowed to crosslink under ambient conditions to form solid films and then were mechanically damaged by creating a scratch.Figure 2A1illustrates a mechanical damage of OXE-CHI-PUR films.When the damaged area is exposed to a 120W fluorescent UV lamp at 302nm wavelength of light for 15(Fig.2A2)and 30(Fig.2A3)min,the damaged area vanishes.The upper portion of Fig.2illustrates IR images of the damaged area,whereas the lower part il-lustrates optical images.Also,IR images of the damaged area exhibit chemical changes resulting from the repair and are shown in figs.S8and S9.A series of controlled experiments were conducted on specimens prepared by varying molar ratios of OXE-CHI with respect to the PUR content (table S1).Optical images shown in Fig.3,A to D,illustrate the results of the experiments conducted under the same UV exposure conditions (0,15,and 30min)conducted on the specimens listed in table S1.
These experiments illustrate that the presence of OXE-CHI precursor is the key factor respon-sible for remendability of the network (Figs.2and 3).Neither PUR nor CHI-PUR alone (table S1,specimens A and B)is able to repair the mechanical damage,whereas the presence of co-valently bonded OXE-CHI (table S1,specimens C and D)entities facilitates the self-healing
process.
Fig.1.Synthetic steps involved in the formation of OXE-CHI.1,Reactions of OXE with CHI,leading to the formation of OXE-CHI precursor;2,Reactions of OXE-CHI with HDI and PEG,leading to formations of remendable OXE-CHI-PUR
network.
Fig.2.IR (upper )and optical (lower )images of OXE-CHI-PUR networks recorded as a UV exposure time.A1,0min;A2,15min;A3,30min.(SOM provides details regarding spectroscopic changes detected by IR imaging.)
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Table S1also shows the damage width as a function of UV exposure evaluations conducted on the specimens shown in Fig.3.The rate of repair for networks containing half the OXE-CHI pre-cursor concentration is also reduced.
Although a cut is a local event at micrometer or smaller scales,the actual cleavage is a molecular-level event.To determine the mechanism of repair and to follow molecular events in the damaged area,we used localized micro-attenuated total reflectance (A TR)Fourier transform IR (FTIR)spectroscopy (22)and internal reflection IR imaging (IRIRI)(23).As shown in figs.S6and S7,the loss of urea and ether linkages of CHI (circled in Fig.1)containing OXE rings results from the UV light exposure of damaged surface areas responsible for repairing.In these experiments,the repair process uses UV light
to recombine free radicals to form crosslinks.In the 280to 400nm range,a fluorescent UV lamp gen-erates approximately 0.3W/m 2per nm power den-sity,whereas the Sun gives off about 0.25W/m 2per nm (24).Thus,the time frames for repair of the Sun exposure are very similar,although the ener-gy density changes as a function of the wavelength of radiation for both sources vary somewhat.As a result of stronger Sun radiation during the summer months in the southern United States,the repair process will be about 3to 4times as fast compared with the equivalent exposure in the northern United States,but for the winter months this difference will be negligible (25).Because crosslinking reactions are not moisture sensitive,dry or humid climate con-ditions will not affect the repair process.The above networks exhibit the ability to self-repair upon expo-sure to UV light,but if exactly the same previously repaired spot is damaged again,the ability for further repair may be limited by the thermosetting character-istics of these networks.
We developed a new generation of thermoset-ting polymers that are of considerable technical and commercial importance.The use of the UV portion of the electromagnetic radiation for re-pairing mechanical damages in coatings offers an ambient temperature approach to self-healing —critical in a number of applications and tech-nologies that do not require the placement of other,often elaborate,network components —that is controlled by the chemistries and morphol-ogies of polymer networks.
References and Notes
1.J.Leon,E.Rojo,J.J.Sanchez-Serrano,J.Exp.Bot.52,1(2001).
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4.G.Henry,W.Li,W.Garner,D.T.Woodley,Lancet 361,574(2003).
5.K.G.Mann,K.Brummel-Ziedins,T.Orefo,S.Butenas,Blood Cells Mol.Dis.36,108(2006).
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8.S.R.White et al .,Nature 409,794(2001).
9.E.N.Brown,M.R.Kessler,N.R.Sottos,S.R.White,J.Microencapsul.20,719(2003).
10.E.N.Brown,S.R.White,N.R.Sottos,J.Mater.Sci.39,
1703(2004).
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34,743(2003).
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(2005).
13.J.W.C.Pang,I.P.Bond,Composites Part A 36,183(2005).14.S.R.Trask,H.R.Williams,I.P.Bond,Bioinspir.Biomim.
2,P1(2007).
15.X.Chen et al .,Science 295,1698(2002).16.R.Gheneim,C.Perez-Berumen,A.Gandini,
Macromolecules 35,7246(2002).
17.S.K.Toohey,N.R.Sottos,J.A.Lewis,J.S.Moore,
S.R.White,Nat.Mater.6,581(2007).
18.P.Cordier,F.Tournilhac,C.Soulie-Ziakovic,L.Leiber,
Nat.Lett.451,977(2008).
19.D.B.Otts,M.W.Urban,Polymer (Guildf.)46,2699(2005).20.Materials and methods and additional data are available
as supporting material on Science Online.
21.Y.Wan,K.A.M.Creber,B.Peppley,V.T.Bui,J.Polym.
Sci.Part B Polym.Phys 42,1379(2004).
22.M.W.Urban,Attenuated Total Reflectance Spectroscopy
of Polymers;Theory and Applications (American Chemical Society and Oxford University Press,Washington,DC,1996)23.D.Otts,P.Zhang,M.W.Urban,Langmuir 18,6473(2002).24.Average Optimum Direct Global Radiation,Miami,FL,USA;
Atlas Material Testing Technology;https://www.doczj.com/doc/3c6678403.html,.25.National Oceanographic and Atmospheric Administration,
2008;https://www.doczj.com/doc/3c6678403.html,/products/stratosphere/uv_index/gif_files/spectrum.gif (https://www.doczj.com/doc/3c6678403.html,).
26.These studies were primarily supported by the National
Science Foundation MRSEC under DMR 0213883and the Materials Research Instrumentation (MRI)Program under DMR 0215873.We thank the Mississippi Division of Marine Resources for partial support.
Supporting Online Material
https://www.doczj.com/doc/3c6678403.html,/cgi/content/full/323/5920/1458/DC1Materials and Methods SOM Text
Figs.S1to S10Table S1References
20October 2008;accepted 29January 2009
10.1126/science.1167391
Fig.3.Optical images of mechanically damaged films:PUR (A1,A2,and A3are images after exposure for 0,15,and 30min to UV radiation;HDI/PEG/CHI =1:1.5:0);CHI-PUR (B1,B2,and B3are images after exposure for 0,15,and 30min to UV radiation;HDI/PEG/CHI =1:1.4:0.57×10?4);OXE-CHI-PUR (C1,C2,and C3are images after exposure for 0,15,and 30min to UV radiation;HDI/PEG/OXE-CHI =1:1.4:0.57×10?4);OXE-CHI-PUR (D1,D2,and D3are images after exposure for 0,15,and 30min to UV radiation;HDI/PEG/OXE-CHI =1:1.33:1.17×10?4).13MARCH 2009VOL 323
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什么是TDI、MDI，聚氨酯的用途 近期经常见诸报端的化工产品TDI，产品价格一路走高、许多大型石化企业纷纷上马，节能减排等等，TDI是什么那，它有什么用途那？解释一二： tdi(甲苯二异氰酯)是常用的多异氰酸酯的一种，而多异氰酯是聚氨酯(pu)材料和重要基础原料。聚氨酯工业最常用的tdi是2，4-tdi两种异构体的混合物，主要用于生产软质聚氨酯泡沫及聚氨酯弹性体、涂料、胶黏剂等。 知道了吗，tdi是生产聚氨酯重要原料，而另一个知名的MDI也是生产聚氨酯重要原料，也是价格备受追捧，那聚氨酯是做什么的那？ 聚氨酯是一种新兴的有机高分子材料，被誉为“第五大塑料”，因其卓越的性能而被广泛应用于国民经济众多领域。产品应用领域涉及轻工、化工、电子、纺织、医疗、建筑、建材、汽车、国防、航天、航空.... 1、PU软泡Flexible PU 垫材——如座椅、沙发、床垫等，聚氨酯软泡是一种非常理想的垫材材料，垫材也是软泡用量最大的应用领域； 吸音材料——开孔的聚氨酯软泡具有良好的吸声消震功能，可用作室内隔音材料； 织物复合材料——垫肩、文胸海绵、化妆棉；玩具 2、PU硬泡Rigid PU 冷冻冷藏设备——如冰箱、冰柜、冷库、冷藏车等，聚氨酯硬泡是冷冻冷藏设备的最理想的绝热材料； 工业设备保温——如储罐、管道等； 建筑材料——在欧美发达国家，建筑用聚氨酯硬泡占硬泡总消耗量的70%左右，是冰箱、冰柜等硬泡用量的一倍以上；在中国，硬泡在建筑业的应用还不像西方发达国家那样普遍，所以发展的潜力非常大； 交通运输业——如汽车顶篷、内饰件（方向盘、仪表盘）等； 仿木材——高密度（密度300~700kg/m3）聚氨酯硬泡或玻璃纤维增强硬泡是结构泡沫塑料，又称仿木材，具有强度高、韧性好、结皮致密坚韧、成型工艺简单、生产效率高等特点，强度可比天然木材高，密度可比天然木材低，可替代木材用作各类高档制品。 灌封材料——例如防水灌浆材料、堵漏材料、屋顶防水材料 花卉行业——PU花盆、插花泥等 3、PU半硬泡Semi-rigid PU 吸能性泡沫体——吸能性泡沫体具有优异的减震、缓冲性能，良好的抗压缩负荷性能及变形复原性能，其最典型的应用是用于制备汽车保险杠； 自结皮泡沫体（Integral Skin Foam）——用于制备汽车方向盘、扶手、头枕等软化性内功能件和内部饰件。自结皮泡沫制品通常采用反应注射模塑成型（Reaction Injection Moulding，简称RIM）加工技术； 微孔弹性体——聚氨酯微孔弹性体最典型的应用是用于制鞋工业。 4、聚氨酯弹性体（PU Elastomers） 浇注型聚氨酯弹性体（简称CPU）——是聚氨酯弹性体中应用最广、产量最大的一种； 热塑型聚氨酯弹性体（简称TPU）——热塑型聚氨酯弹性体约占聚氨酯弹性体总量的25%左右； 混炼型聚氨酯弹性体（简称MPU）——占聚氨酯弹性体总量的10%左右。 实心轮胎；印刷、输送胶辊；压型胶辊；油封、垫圈球节、衬套轴承；O型圈；撑垫；鞋底、后根、包头；衬里；齿轮等，不同应用领域，选择的弹性体的硬度范围不同。 在矿山、冶金等行业的应用——筛板、摇床等 在机械工业方面的应用——胶辊、胶带、密封件等； 在汽车工业方面的应用——轮胎、密封圈等； 在轻工业方面的应用——聚氨酯鞋底料、聚氨酯合成革、聚氨酯纤维； 在建筑工业方面的应用——防水材、铺装材、灌封材等。 5、聚氨酯鞋底料（Shoe Sole） 聚氨酯鞋底具有诸多优点：密度低，质地柔软，穿着舒适轻便；尺寸稳定性好，储存寿命长；优异的耐磨性能、耐挠曲性能；优异的减震、防滑性能；较好的耐温性能；良好的耐化学品性能等等。聚氨酯多用于制造高档
金属填充复合材料修 补金属件
金属填充复合材料修补金属件 金属填充复合材料修补金属件 一、为什么使用Loctite? Fixmaster?金属填充复合材料？ Loctite? Fixmaster? 金属填充复合材料可为设备因冲击及机械损伤造成的缺陷提供维修解决方案，如套的裂纹，轴及套的磨损等。 Loctite? Fixmaster?金属填充复合材料可有效修复和重建机械设备的损伤不需要加热和焊接。 传统方式 VS. 现代解决方案 传统方式如硬表面堆焊需大量的时间，成本昂贵。Loctite? Fixmaster?金属填充复合材料操作方便，具有优良的抗压强度。可以给设备提供有效的保护。Loctite? Fixmaster?金属填充复合材料和Loctite? Nordbak?耐磨防护剂可修复不同类的磨损，使其可重新投入使用。 二、Loctite? Fixmaster?金属填充复合材料的优点： （1）、快速维修 （2）、可选择钢粉、铝粉或非金属填充 （3）、低收缩率 （4）、耐久维修 （5）、使用方便 （6）、高抗压强度 （7）、不需加热
（8）、可在线维修 （9）、类似金属色 （10）、固化后可钻孔、攻丝和机械加工 （12）、与金属，陶瓷，木材.玻璃和部分塑料良好的粘结力 三、选择Loctite? Fixmaster?金属填充复合材料时需考虑的关键因素 金属修补Loctite? Fixmaster?复合材料填充钢粉或铝粉等不同金属粉末，使在维修时尽可能接近设备本体性能，非金属填充的产品用于修复磨损严重的场合。产品一致性产品粘度满足客户的不同需求，Loctite? Fixmaster?产品粘度分为浇铸型、膏状及棒状可供选择。 特殊需求对于一些特殊场合的应用，汉高拥有一些有特殊性能的产品，如高抗压强度，耐高温或耐磨产品可供选择。 四、表面处理正确的表面处理是这些产品成功应用的关键因素。 好的表面处理可以增加Loctite? Fixmaster?复合材料与部件的粘附力；防止金属表面与Loctite? Fixmaster?复合材料之间锈蚀；延长产品使用寿命。 正确的表面处理必须干净和干燥；无表面及内部化学污染；无锈蚀；表面粗糙度75um以上。 五、产品应用 Loctite? Fixmaster?金属填充复合材料是双组合环氧产品，应用之前必须按正确的比例混合至颜色均一为止。 膏状产品使用时必须紧刮于设备表面且达到所需要的厚度，请注意使用过程中需防止气泡的混入。
the formation of prenucleation clusters with dimen-sions of 0.6to 1.1nm (step 0).In analogy to the chemistry of calcium phosphate (31),we consider them to be the smallest stable agglomerates of CaCO 3present from the beginning of the reaction.Aggregation of these clusters in solution leads to the nucleation of ACC nanoparticles with a size distri-bution centered around 30nm (step 1).Association of these particles with the template surface initiates the growth of ACC (step 2),using the nanoparticles in their neighborhood as feedstock.Next,randomly oriented nanocrystalline domains are formed inside the otherwise amorphous particles (steps 3and 4).On the basis of the model of Zhang et al .(23),we expect these domains to be unstable and in equi-librium with the amorphous phase.In the last steps,the orientation that is stabilized through the inter-action with the monolayer becomes dominant (step 5)and develops into a single crystal (step 6).This single crystal probably grows by the further addition and incorporation of ions and clusters from solution.The initial experiments of Mann and co-workers showed that the present system could produce cal-cite (11.0)or vaterite (00.1)depending on the pre-cise conditions (16,32).Later,it was demonstrated that rapid CO 2evaporation favors the kinetic product,vaterite (21,22),whereas lower evaporation rates lead to the calcitic form (21).These results are confirmed by our finding of (00.1)oriented vaterite in the present work (i.e.,in a fast-outgassing thin film)and the formation of (11.0)oriented calcite in crystallization dishes (fig.S7)(15)from which CO 2outgassing is slower.Moreover,the observation of randomly oriented vaterite crystals also puts in perspective the synchrotron x-ray scattering exper-iments that showed the formation of randomly oriented crystals from the same system (22). The nanoscopic prenucleation clusters that we visualized are the smallest stable form of CaCO 3and are likely the building blocks of the amorphous precursor particles observed in biomineralization;such particles are also observed in many synthetic systems and are not restricted to calcium carbonate (13,31).As a consequence of their aggregation,ACC nucleates in solution and subsequently assembles at the template.There,it is present as a temporarily stabilized but transient phase that mediates the trans-fer of information from the template to the mineral phase.This occurs through the selective stabiliza-tion of only one of the orientations present,leading to the development of a single crystal. References and Notes 1.H.A.Lowenstam,S.Weiner,On Biomineralization (Oxford Univ.Press,New York,1989). 2.M.E.Davis,Science 305,480(2004). 3.B.L.Smith et al .,Nature 399,761(1999). 4.J.Aizenberg et al .,Science 309,275(2005). 5.J.R.Young,J.M.Didimus,P.R.Bown,B.Prins,S.Mann,Nature 356,516(1992). 6.L.Addadi,D.Joester,F.Nudelman,S.Weiner,Chem.Eur.J.12,980(2006). 7.N.A.J.M.Sommerdijk,G.de With,Chem.Rev.108,4499(2008). 8.M.Volmer,Kinetik der Phasenbildung (Steinkopff,Dresden,1939). 9.Y.Politi,T.Arad,E.Klein,S.Weiner,L.Addadi,Science 306,1161(2004). 10.E.Beniash,J.Aizenberg,L.Addadi,S.Weiner,Proc.R. Soc.London Ser.B 264,461(1997). 11.B.P.Pichon,P.H.H.Bomans,P.M.Frederik, N.A.J.M.Sommerdijk,J.Am.Chem.Soc.130,4034(2008).12.J.R.I.Lee et al .,J.Am.Chem.Soc.129,10370(2007).13.D.Gebauer,A.V?lkel,H.C?lfen,Science 322,1819(2008).14.C.L.Freeman,J.H.Harding,D.M.Duffy,Langmuir 24, 9607(2008). 15.See supporting material on Science Online. 16.S.Mann,B.R.Heywood,S.Rajam,J.D.Birchall,Nature 334,692(1988). 17.S.Nickell,C.Kofler,A.P.Leis,W.Baumeister,Nat.Rev. Mol.Cell Biol.7,225(2006). 18.The sedimentation coefficient s is defined as the velocity v t of the particle per unit gravitational acceleration (centrifugal acceleration:w 2r ,where w is angular velocity and r is the radial distance to the rotation axis).19.F.M.Michel et al .,Chem.Mater.20,4720(2008).20.D.Quigley,P.M.Rodger,J.Chem.Phys.128,221101(2008).21.E.Loste,E.Diaz-Marti,A.Zarbakhsh,F.C.Meldrum, Langmuir 19,2830(2003). 22.E.DiMasi,M.J.Olszta,V.M.Patel,L.B.Gower, CrystEngComm 5,346(2003). 23.T.H.Zhang,X.Y.Liu,J.Am.Chem.Soc.129,13520(2007).24.Y.Politi et al .,Adv.Funct.Mater.16,1289(2006)https://www.doczj.com/doc/3c6678403.html,m,J.M.Charnock,A.Lennie,F.C.Meldrum, CrystEngComm 9,1226(2007). 26.J.Aizenberg,D.A.Muller,J.L.Grazul,D.R.Hamann, Science 299,1205(2003). 27.R.Tang et al .,Angew.Chem.Int.Ed.43,2697(2004).28.G.Luquet,F.Marin,C.R.Palevol 3,515(2004). 29.L.Brecevic,A.E.Nielsen,J.Cryst.Growth 98,504(1989).30.J.J.J.M.Donners,B.R.Heywood,E.W.Meijer,R.J.M.Nolte, N.A.J.M.Sommerdijk,Chem.Eur.J.8,2561(2002).31.A.S.Posner,F.Betts,Acc.Chem.Res.8,273(1975).32.S.Rajam et al .,J.Chem.Soc.Faraday Trans.87,727(1991).33.Supported by the European Community (project code NMP4-CT-2006-033277)and the Netherlands Organization for Scientific Research (NWO).We thank A.V?lkel and H.C?lfen for performing and evaluating the ultracentrifugation measurements;D.Gebauer and A.Verch for time-dependent solution composition determination of the mineralization solutions; F.L.Boogaard,E.J.Creusen,J.J.van Roosmalen,and P.Moeskops for their contribution to the 3D reconstructions of the tomograms;and P.T.K.Chin for providing the CdSe nanorods. Supporting Online Material https://www.doczj.com/doc/3c6678403.html,/cgi/content/full/323/5920/1455/DC1Materials and Methods SOM Text Table S1 Figs.S1to S7 5December 2008;accepted 30January 200910.1126/science.1169434 Self-Repairing Oxetane-Substituted Chitosan Polyurethane Networks Biswajit Ghosh and Marek W.Urban * Polyurethanes have many properties that qualify them as high-performance polymeric materials,but they still suffer from mechanical damage.We report the development of polyurethane networks that exhibit self-repairing characteristics upon exposure to ultraviolet light.The network consists of an oxetane-substituted chitosan precursor incorporated into a two-component polyurethane.Upon mechanical damage of the network,four-member oxetane rings open to create two reactive ends.When exposed to ultraviolet light,chitosan chain scission occurs,which forms crosslinks with the reactive oxetane ends,thus repairing the network.These materials are capable of repairing themselves in less than an hour and can be used in many coatings applications,ranging from transportation to packaging or fashion and biomedical industries. W hen a hard or sharp object hits a ve-hicle,it is likely that it will leave a scratch,and for this reason the auto-motive industry looks for coatings with high scratch resistance.Because of their hardness and elasticity,polyurethanes exhibit good scratch re-sistance but can still suffer from mechanical dam-age.An ideal automotive coating would mend itself while a vehicle is driven.To heal mechan-ical damage in plants,suberin,tannins,phenols,or nitric oxide are activated to prevent further lesions (1–3),whereas in a human skin,the outer flow of blood cells is arrested by the crosslink network of fibrin,giving rise to wound-healing (4,5).Concentration gradients or stratification in living organisms inspired the development of spa-tially heterogeneous remendable polymers (6,7),composites containing micro-encapsulated spheres (8–11),encapsulated fibers (12–14),reversible cross-linking (15,16),and microvascular networks (17).One example is epoxy matrices containing a glass hollow fiber filled with a monomer and an initiator with the “bleeding ”ability to heal poly-mer networks during crack formation (12).A sim-ilar phenomenon was used in another approach,in which a micro-encapsulated dicyclopentadiene monomer was introduced in a catalyst-embedded polymer matrix,which healed the crack near the ring opening of the monomer (8–11).Reversibil-ity of Diels-Alder reactions resulted in another approach to thermally repair damaged areas,and approach using malemide-furan adducts (15,16).Mimicking of microvascular structures (17),water-responsive expandable gels (7),and formation of supramolecular assemblies (18)are other ave-nues of remendability. This study departs from previous approaches and reports the development of heterogeneous School of Polymers and High Performance Materials,Shelby F.Thames Polymer Science Research Center,The University of Southern Mississippi,Hattiesburg,MS 39406,USA.*To whom correspondence should be addressed.E-mail:marek.urban@https://www.doczj.com/doc/3c6678403.html, 13MARCH 2009VOL 323 SCIENCE https://www.doczj.com/doc/3c6678403.html, 1458 REPORTS
聚氨酯 聚氨酯的工业生产主要是由多元有机异氰酸酯和各中氢给予体化合物（通常如含端羟基的多元醇化合物）反应制备。选择不同数目的官能基团和不同类型的官能基，采用不同的合成工艺，能制备出性能各异、表现形式各种各样的聚氨酯产品：泡沫塑料，弹性橡胶，油漆、涂料，合成纤维、合成皮革、胶黏剂等。应用范围从航空飞行器到工农业生产，从文体娱乐器械到人们日常的衣食住行。 聚氨酯化学中的最基本反应：含活泼氢的醇类化合物所含的羟基与异氰酸酯进行亲核加成反应，生成氨基甲酸酯基团。 异氰酸酯 氨基甲酸酯基团是内聚能较大的特性基团，空间体积较大，在聚合物中具有硬链段特征。而聚氨酯实际上就是由刚性基团（链段）和软链段构成的嵌段共聚物。 异氰酸酯中常见的R基的吸电子能力的基本顺序为：硝基苯基＞苯基＞甲苯基＞苯亚甲基＞烷基。 异氰酸酯与聚醇低聚物反应：1 异氰酸基＞羟基，端基为异氰酸基，主要用于PU弹性体、黏合剂、涂料以及二步法合成PU泡沫塑料等； 2 异氰酸基=羟基，主要用于泡沫塑料和热塑性聚氨酯材料制备； 3 异氰酸基＜羟基，端基为羟基，使用情况较少，主要用于便于贮存的生胶、黏合剂和某些中间体的制备。 小分子醇类主要用作扩链剂、反应润滑剂等参与反应并生成氨基甲酸酯基团。 异氰酸酯与苯酚反应的过程可逆，利用这种可逆反应制备封闭型异氰酸酯衍生物从而应用于单组份聚氨酯黏合剂、涂料、弹性体等产品的合成中。 异氰酸酯与水反应可生成二氧化碳，水因此被用作为最廉价的化学发泡剂，但该反应放热量大且会产生脲基。 异氰酸酯与羧酸反应的反应活性较低，远低于伯醇或水与异氰酸酯间的反应活性，在正常的生产条件下很少能参与反应。 异氰酸酯与胺的反应，胺类化合物大多都呈现一定的碱性，反应速度远快于异氰酸基与羟基的反应速度，即胺类化合物与异氰酸酯的反应速度要比其他含活泼氢化合物高得多。 异氰酸酯与脲基、胺酯基等的反应，能在生成的聚合物中提供一定支链结构，改善了聚氨酯制品的力学性能。 异氰酸酯的自聚反应，异氰酸酯二聚体的生成反应仅局限于芳香族异氰酸酯，而异氰酸酯三聚体在芳香族和脂肪族异氰酸酯中都可以由反应制备。三聚体的碳氮原子六节环结构热稳定性好，使得聚氨酯具备更好的耐热性能，可用于硬质泡沫塑料的制备。 异氰酸酯的自缩聚反应，二异氰酸酯在加热和有机磷催化剂的存在下发生自缩聚反应生成碳化二亚胺，可用于制备抗水解稳定剂；制备液化MDI；提高聚氨酯材料的耐水解能力。 在聚氨酯工业中主要使用的是含有两个或两个以上异氰酸基的有机二异氰酸酯和有机多异氰酸酯。按分子结构：芳香族异氰酸酯、脂肪族异氰酸酯和脂环族多异氰酸酯。按功能特点：通用型多异氰酸酯、非黄变型多异氰酸酯、“无机”元素型多异氰酸酯及异氰酸酯三聚体衍生物、屏蔽型异氰酸酯衍生物等。 通用型有机异氰酸酯主要有TDI、MDI和多苯基甲烷多异氰酸酯（PAPI）等，制备工艺成熟，但存在光照黄变的缺点。 聚氨酯黄变机理：芳香族异氰酸酯形成的芳香族胺酯键受紫外线照射后分解生成芳胺并与苯环产生共振重排，生成共轭醌式结构的生色团。
龙源期刊网 https://www.doczj.com/doc/3c6678403.html, 复材零件修补方法探索 作者：武彬彬 来源：《科技风》2017年第07期 摘要：随着对飞机性能要求的不断提高，复合材料零件将更加广泛的应用于飞机的各个结构中。已经迅速发展为继铝合金、钛合金之后的又一航空结构材料。但是复合材料零件固然有很多优点，但是，复合材料零件的缺陷修补一直是制约复合材料零件发展的制约条件之一。本文对复合材料零件在实际使用过程中常见的缺陷进行了分类分析，对修补方法进行了初步的研究，为其制定合适的修补方法，减少浪费，降低复合材料应用成本。 关键词：复合材料；缺陷；修补 复合材料零件加工制造过程不同于金属零件，在成型过程中，装配过程中，使用过程中均会出现不同的缺陷。在生产实践中，即使是经过研究和试验制定的合理工艺，在结构件的制造过程还可能产生缺陷，引起质量问题，严重时还会导致整个结构件的报废，造成重大经济损失。因此，研究复合材料，尤其是国产碳纤维复合材料结构件的缺陷分类及维修方法是目前迫切需要解决的问题。 随着我国飞机数量的增加和换代速度的加快，复合材料用量也越来越大，修补的重要性也就越来越凸显。但是，国内在修补方面还是参考国外的一些文献和资料，照葫芦画瓢。而且目前国内对复合材料零件的修补还是没有进行验证，产品设计对此领域还是持保守状态。 对复合材料结构提出的修补要求主要有： ①恢复结构的70%承载能力和使用功能，即恢复结构的基本完整性； ②修理后重量不能增加太多； ③尽量保证原结构外形。 一、缺陷类型 根据目前国内复合材料制件结构及形成时段状态，缺陷存在的类型可以分为以下几类： ①实体层压板缺陷类型：零件分层、贫胶、皱折、鼓包、分层、杂质、打磨过分或伤及纤维的损伤、边缘分层损伤等缺陷。 ②针对复合材料蜂窝夹层件的缺陷类型：蜂窝芯格压缩、蜂窝芯凹陷、芯子与蒙皮分层等缺陷。
图５一配方中加入Ａ?３３后泡沫的温度变化率及上升速率 表示时间变化），也说明后期几乎不发生三聚反应三这是因为Ａ?３３是强凝胶催化剂，催化ＮＣＯ基与ＯＨ基反应形成聚氨酯网状结构，导致ＮＣＯ基团间接触机会少，很难发生三聚反应，导致泡沫发软二强度低三 ３一结论 （１）聚氨酯泡沫反应中不同阶段的速率二温度变化二高度变化可以体现在Ｆｏａｍａｔ发泡曲线中三（２）ＰＩＲ改性聚氨酯硬泡的发泡试验中上升速率曲线可出现两个峰，针对两个峰的大小及距离可以对配方进行优化设计三 （３）利用Ｆｏａｍａｔ泡沫起升测试仪可以显示不同沸点的发泡剂在发泡曲线中差异，还可以判定催化剂对聚氨酯发泡的催化选择性三 参一考一文一献 ［１］一吕晓奇，于大海，朱彦等．浅析聚氨酯泡沫起升试验与反应过程［Ｊ］．聚氨酯工业，２０１５，３０（１）：４４－４６． ［２］一刘访艺，王浩臻，蒋小龙，等．ＨＦＣ?２４５ｆａ对聚氨酯硬泡板材性能影响的研究［Ｊ］．聚氨酯工业，２０１７，３２（４）：２７－３０．［３］一朱吕民，刘益军．聚氨酯泡沫塑料［Ｍ］．３版．北京：化学工业出版社，２００５． ［４］一刘益军．聚氨酯原料及助剂手册［Ｍ］．２版．北京：化学工业出版社，２００５． ［５］一江永飞．聚氨酯硬泡中替代ＣＦＣ－１１的发泡剂［Ｊ］．黎明化工，１９９５（４）：１２－１４． 收稿日期一２０１８－０５－２７一一修回日期一２０１８－０８－０９ ＡｐｐｌｉｃａｔｉｏｎｏｆＦｏａｍａｔＦｏａｍＲｉｓｉｎｇＩｎｓｔｒｕｍｅｎｔｉｎＰｏｌｙｕｒｅｔｈａｎｅＦｏａｍｉｎｇ ＤＯＵＺｈｏｎｇｓｈａｎ，ＷＡＮＧＬｅｉ，ＬＩＵＹｏｎｇｌｉａｎｇ，ＷＡＮＧＹａｏｘｉ，ＬＩＸｉａｏｊｉｎｇ （ＷａｎｈｕａＥｎｅｒｇｙｓａｖＳｃｉｅｎｃｅ＆ＴｅｃｈｎｏｌｏｇｙＧｒｏｕｐＣｏ．Ｌｔｄ，Ｙａｎｇｔａｉ，Ｓｈａｎｄｏｎｇ２６４０００，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：Ａｓｅｒｉａｌｏｆｓｔｕｄｙｗｅｒｅｃａｒｒｉｅｄｂａｓｅｄｏｎａｐｏｌｙｉｓｏｃｙａｎｕｒａｔｅｍｏｄｉｆｉｅｄｒｉｇｉｄｐｏｌｙｕｒｅｔｈａｎｅｆｏａｍｆｕｎｄａ?ｍｅｎｔａｌｆｏｒｍｕｌａ．ＴｈｅａｐｐｌｉｃａｔｉｏｎｏｆＦｏａｍａｔｆｏａｍｒｉｓｉｎｇｉｎｓｔｒｕｍｅｎｔｏｎｔｈｅｆｏａｍｉｎｇｃｕｒｖｅｉｎｄｉｆｆｅｒｅｎｔｆｏａｍｉｎｇｓｙｓｔｅｍｓｗｉｔｈｄｉｆｆｅｒｅｎｔｂｌｏｗｉｎｇａｇｅｎｔ，ｃａｔａｌｙｓｔｓｅｌｅｃｔｉｏｎａｎｄｅｘｐｌａｉｎｉｎｇｏｆｆｏａｍｉｎｇｐｈｅｎｏｍｅｎａｗｅｒｅｉｎｔｒｏｄｕｃｅｄ．Ｋｅｙｗｏｒｄｓ：Ｆｏａｍａｔｆｏａｍｒｉｓｉｎｇｉｎｓｔｒｕｍｅｎｔ；ｒｉｇｉｄｐｏｌｙｕｒｅｔｈａｎｅｆｏａｍ；ｐｏｌｙｉｓｏｃｙａｎｕｒａｔｅｆｏａｍ 作者简介一窦忠山一男，１９８７年出生，本科学历，研究方向为聚氨酯硬泡三 自修复聚氨酯弹性体材料研究方面取得新进展 自修复聚合物材料作为一种智能材料，可以修复在使用过程中因外力作用而产生的裂纹或局部损伤，从而恢复其原有的功能，延长其使用寿命三该材料在表面镀层保护二生物医药材料二锂电池以及航空航天等领域具有潜在的应用前景三为了满足不同的应用，研究人员将 牺牲键 引入到聚合物材料中，开发了自修复塑料二凝胶或弹性体三对于自修复弹性体材料来说，兼顾良好的机械性能二高效的自修复效率及优异的光学性能是一个挑战性难题三 在国家自然科学基金委的支持下，中国科学院化学研究所工程塑料重点实验室研究员董侠等致力于智能材料的开发与应用，取得了系列进展三在此基础上，从分子设计角度出发，提出了一种新型自修复设计策略 ＰｈａｓｅＬｏｃｋｅｄ ＤｙｎａｍｉｃＣｈｅｍｉｃａｌＢｏｎｄｓ（相锁定动态化学键） ，成功制备出无色透明二可快速自修复的高韧高强聚合物三 研究工作通过 硬段锁定 和 微相分离控制 相结合的策略展开，设计的含二硫键自愈聚氨酯弹性体（ＰＵＤＳ）呈现出无色透明的优异光学性质，最大拉伸强度可达２５ＭＰａ，断裂伸长率超过１６００％，在温和加热条件下（７０?），弹性体表面划痕可在６０ｓ内迅速恢复，同时表现出良好的重复刮擦自修复功能，经多次刮擦自修复后材料的雾度值仅为０ ６％三这种无色高透明的自修复特征，使得该材料在光学领域具有重要的应用前景三相关成果发表于‘先进材料“三 四６３四聚氨酯工业一一一一一第３３卷
玻璃纤维材料的修复 -----------------------------------------------------------------------------------------其他行业的玻璃纤维修复 1.汽车保险杠是玻璃钢的，损坏了只能用玻璃纤维和树脂来修补，首先你需要买树脂和玻璃纤维毡，这些卖玻璃钢产品的门市都有的，树脂论公斤卖的，叫他们给你配好了，因为其实它有三种材料：树脂、催干剂和固化剂，问清楚怎么用？因为都是化学材料，三者放在一起会起化学反应，放热的，量大的话还会爆炸的，所以要注意安全，不要被烫到了，不要被溅到眼睛里；玻璃纤维布注意最好买毡，因为毡是丝状的，可以一根根抽出来，便于修复修平汽车保险杠表面。两者都买好了，开始修理了：拿个容器另外装树脂，少装些，别一次倒完了，然后再放几滴固化剂，注意搅拌均匀，固化剂可以少放，因为他起固化作用，少放固化慢一些就是了，放多了几分钟就完全固化了，你还没来的及修补呢！用个毛刷刷到到损坏的地方，然后贴些玻璃纤维毡，再刷些树脂上去，刷一次贴一次就可以了！干了以后打磨表面，最后喷漆就可以了！做玻璃这行看起来简单，其实也是技术活，要熟练才刷的平，没有空隙才行！液体是不饱和聚酯树脂【型号一般时191和196】但是要加固化剂和促进剂【俗称红水和白水】比例根据温度而不同，调和后要在规定时间内糊完，否则就会固化 2.买玻璃丝布，环氧树脂，固化剂和柔软剂，先把破口处理一下，再刷环氧树脂混合液，后铺玻璃丝布，这样做三脂两布，固化后，打磨平整。 玻璃钢（FRP）亦称作GFRP，即纤维强化塑料，一般指用玻璃纤维增强不饱和聚酯、环氧树脂与酚醛树脂基体。以玻璃纤维或其制品作增强材料的增强塑料，称谓为玻璃纤维增强塑料，或称谓玻璃钢，注意与钢化玻璃区别开来。由于所使用的树脂品种不同，因此有聚酯玻璃钢、环氧玻璃钢、酚醛玻璃钢之称。质轻而硬，不导电，性能稳定.机械强度高，回收利用少，耐腐蚀。可以代替钢材制造机器零件和汽车、船舶外壳等。 3.树脂和纤维都是玻璃钢的原材料，在混合固化剂和促进剂、在一定温度作用下，粘有树脂的玻璃纤维，因树脂的固化而被粘合在一起，就形成了玻璃钢材质。玻璃钢具有高强、轻质、耐腐蚀的特点，属于复合材料，也就是集合了多种材料的优点而制作出的一种材料。玻璃钢有狭义范畴和广义范畴的说法，狭义就是指玻璃纤维和树脂制作而成的，而广义的玻璃钢，还包括树脂和其它纤维制作成的复合材料，比如碳纤维玻璃钢（比如多数钓鱼竿）、涤纶纤维玻璃钢等等。 4.玻璃钢开裂怎么办 沿着裂缝周围用粗砂纸磨成粗糙，后用树脂和玻璃钢纤维补上 那如果非要修的话，也不是没有办法。树脂选用好点的，一般的也行，还有促进剂、固化剂、优质玻璃纤维布。粉子就不要放了。现在是秋季，温度低，所以固化剂要比夏天时多放，至于精确的比例，我随便估摸一下应该是：固化剂、促进剂、树脂；1：1.5：8 配合玻璃纤维缠在管道上，要让配好的玻璃钢迅速的涂在玻璃纤维布上，要让玻璃钢把玻璃纤维布充分浸透，等待玻璃钢充分固化后，再反复做上几层。就会结实了 航空复合材料结构修理方法 --------------------------------------------------------------------------------------适用于整流罩和玻璃纤维蒙皮1. 1复合材料的缺陷/ 损伤与修理容限
聚氨基甲酸酯 百科名片 聚氨基甲酸酯 聚氨酯全称为聚氨基甲酸酯,是主链上含有重复氨基甲酸酯基团的大分子化合物的统称。它是由有机二异氰酸酯或多异氰酸酯与二羟基或多羟基化合物加聚而成。 目录 聚氨基甲酸酯 聚氨酯涂层剂 行业发展 施工工艺 用作鲨鱼皮泳衣 相关新闻 展开 编辑本段聚氨基甲酸酯 基本信息 中文名：聚氨基甲酸酯；聚氨酯 聚氨基甲酸酯 拼音：jù ān jī jiǎ suān zhǐ 前言聚氨酯全称为聚氨基甲酸酯,是主链上含有重复氨基甲酸酯基团(ＮＨＣＯＯ)的大分子化合物的统称。它是由有机二异氰酸酯或多异氰酸酯与二羟基或多羟基
化合物加聚而成。聚氨酯大分子中除了氨基甲酸酯外,还可含有醚、酯、脲、缩二脲,脲基甲酸酯等基团。聚氨酯的结构 英文名：polyurethane 研发历史 聚氨酯(简称TPU)是由多异氰酸酯和聚醚多元醇或聚酯多元醇或/及小分子多元醇、多元胺或水等扩链剂或交联剂等原料制成的聚合物。通过改变原料种类及组成，可以大幅度地改变产品形态及其性能，得到从柔软到坚硬的最终产品。聚氨酯制品形态有软质、半硬质及硬质泡沫塑料、弹性体、油漆涂料、胶粘剂、密封胶、合成革涂层树脂、弹性纤维等，广泛应用于汽车制造、冰箱制造、交通运输、土木建筑、鞋类、合成革、织物、机电、石油化工、矿山机械、航空、医疗、农业等许多领域。 1937年德国Otto Bayer教授首先发现多异氰酸酯与多元醇化合物进行加聚反应可制得聚氨酯，并以此为基础进入工业化应用，英美等国1945～1947年从德国获得聚氨酯树脂的制造技术于1950年相继开始工业化。日本1955年从德国Bayer公司及美国DuPont公司引进聚氨酯工业化生产技术。20世纪50年代末我国聚氨酯工业开始起步，近lO多年发展较快。 制备来源 由二元或多元异氰酸酯与二元或多元羟基化合物作用而成的高分 聚氨基甲酸酯 子化合物。 聚氨基甲酸酯，是分子结构中含有—NHCOO—单元的高分子化合物，该单元由异氰酸基和羟基反应而成，反应式如下： —N=C=O + HOˉ → —NH-COOˉ 聚氨酯的发现：20世纪30年代，德国Otto Bayer 首先合成了TPU。在1950年前后，TPU作为纺织整理剂在欧洲出现，但大多为溶剂型产品用于干式涂层整理。20世纪60年代，由于人们环保意识的增强和政府环保法规的出台，水系TPU涂层应运而生。70年代以后，水系PU涂层迅速发展，PU涂层织物已广泛应用。80年代以来，TPU的研究和应用技术出现了突破性进展。与国外相比，国内关于PU纺织品整理剂的研究较晚。 主要用途
聚氨酯是一种新兴的有机高分子材料，被誉为“第五大塑料”，因其卓越的性能而被广泛应用于国民经济众多领域。产品应用领域涉及轻工、化工、电子、纺织、医疗、建筑、建材、汽车、国防、航天、航空.... 1、PU软泡Flexible PU 垫材——如座椅、沙发、床垫等，聚氨酯软泡是一种非常理想的垫材材料，垫材也是软泡用量最大的应用领域； 吸音材料——开孔的聚氨酯软泡具有良好的吸声消震功能，可用作室内隔音材料； 织物复合材料——垫肩、文胸海绵、化妆棉；玩具 2、PU硬泡Rigid PU 冷冻冷藏设备——如冰箱、冰柜、冷库、冷藏车等，聚氨酯硬泡是冷冻冷藏设备的最理想的绝热材料； 工业设备保温——如储罐、管道等； 建筑材料——在欧美发达国家，建筑用聚氨酯硬泡占硬泡总消耗量的70%左右，是冰箱、冰柜等硬泡用量的一倍以上；在中国，硬泡在建筑业的应用还不像西方发达国家那样普遍，所以发展的潜力非常大； 交通运输业——如汽车顶篷、内饰件（方向盘、仪表盘）等； 仿木材——高密度（密度300~700kg/m3）聚氨酯硬泡或玻璃纤维增强硬泡是结构泡沫塑料，又称仿木材，具有强度高、韧性好、结皮致密坚韧、成型工艺简单、生产效率高等特点，强度可比天然木材高，密度可比天然木材低，可替代木材用作各类高档制品。 灌封材料——例如防水灌浆材料、堵漏材料、屋顶防水材料 花卉行业——PU花盆、插花泥等 3、PU半硬泡Semi-rigid PU 吸能性泡沫体——吸能性泡沫体具有优异的减震、缓冲性能，良好的抗压缩负荷性能及变形复原性能，其最典型的应用是用于制备汽车保险杠； 自结皮泡沫体（Integral Skin Foam）——用于制备汽车方向盘、扶手、头枕等软化性内功能件和内部饰件。自结皮泡沫制品通常采用反应注射模塑成型（Reaction Injection Moulding，简称RIM）加工技术； 微孔弹性体——聚氨酯微孔弹性体最典型的应用是用于制鞋工业。 4、聚氨酯弹性体（PU Elastomers） 浇注型聚氨酯弹性体（简称CPU）——是聚氨酯弹性体中应用最广、产量最大的一种； 热塑型聚氨酯弹性体（简称TPU）——热塑型聚氨酯弹性体约占聚氨酯弹性体总量的25%左右； 混炼型聚氨酯弹性体（简称MPU）——占聚氨酯弹性体总量的10%左右。 实心轮胎；印刷、输送胶辊；压型胶辊；油封、垫圈球节、衬套轴承；O型圈；撑垫；鞋底、后根、包头；衬里；齿轮等，不同应用领域，选择的弹性体的硬度范围不同。 在矿山、冶金等行业的应用——筛板、摇床等 在机械工业方面的应用——胶辊、胶带、密封件等； 在汽车工业方面的应用——轮胎、密封圈等； 在轻工业方面的应用——聚氨酯鞋底料、聚氨酯合成革、聚氨酯纤维； 在建筑工业方面的应用——防水材、铺装材、灌封材等。 5、聚氨酯鞋底料（Shoe Sole） 聚氨酯鞋底具有诸多优点：密度低，质地柔软，穿着舒适轻便；尺寸稳定性好，储存寿命长；优异的耐磨性能、耐挠曲性能；优异的减震、防滑性能；较好的耐温性能；良好的耐化学品性能等等。聚氨酯多用于制造高档皮鞋、运动鞋、旅游鞋等。