D570-98塑料吸水率的试验方法

一、概述硬质泡沫塑料是一种常见的材料，在工业、建筑和包装行业都有广泛的应用。

为了确保其质量和性能能够满足要求，我们需要对其吸水率进行测试。

本指导书旨在对硬质泡沫塑料的吸水率试验进行详细的介绍，确保测试的准确性和可靠性。

二、试验目的1. 了解硬质泡沫塑料对水的吸收能力。

2. 评估硬质泡沫塑料在潮湿环境下的稳定性。

3. 为材料的选材和设计提供参考依据。

三、试验原理硬质泡沫塑料的吸水率指的是单位时间内被吸收水的质量与材料自身质量的比值。

通常使用以下公式进行计算：吸水率 = （吸水后的质量 - 干燥前的质量）/ 干燥前的质量× 100四、试验仪器和设备1. 电子天平2. 恒温恒湿箱3. 干燥器4. 测量容器5. 质量计6. 洁净毛刷五、试验样品准备1. 选择代表性的硬质泡沫塑料样品。

2. 按照标准要求，将样品切割成规定的尺寸。

3. 称量并记录每个样品的初始质量。

六、试验步骤1. 将待测试的样品放入恒温恒湿箱中，设置合适的温度和湿度参数。

2. 设置吸水时间，通常为24小时。

3. 取出样品，用干燥器将其表面的自由水蒸发干净。

4. 使用电子天平精确称量吸水后的样品质量，并记录。

5. 根据试验原理计算吸水率，并记录。

七、数据处理与分析1. 根据试验结果计算吸水率的平均值，并进行统计分析。

2. 将试验数据与标准要求进行对比，评估样品的吸水性能。

八、注意事项1. 样品的选择应该具有代表性，能够反映整批产品的性能。

2. 在试验过程中要注意维持恒温恒湿箱内的环境参数稳定。

3. 进行试验前要对仪器和设备进行校准和检查，确保准确性。

九、安全注意事项1. 在操作试验设备时要注意安全，防止发生意外。

2. 根据设备使用说明书正确操作，防止损坏设备和样品。

十、总结本试验指导书详细介绍了硬质泡沫塑料吸水率试验的具体步骤和注意事项，希望能够对进行相关试验的学生和工作者提供帮助。

在进行试验时，要严格按照标准要求进行操作，确保结果的准确性和可靠性。

建筑材料试验--吸水率试验
1.试验目的
吸水率可估算材料的其他性质，如耐水性、抗冻性、抗风化性等。

2.主要仪器设备
(1)天平（感量0.01g)。

(2)烘箱。

(3)容器等。

3.试样制备
将试件置于烘箱中，以（105±5)℃的温度烘干至恒重，取出放入干燥器中冷却至室温待用。

4.试验步骤
(1)用天平称量试样的质量m1(g)(精确至0.01g),再将试样放入容器底部算板上，使试件底面与盆底不致紧贴，使水能够自由进入。

(2)加水至试件高度的1/4处；以后每隔2h分别加水至高度的1/2和3/4处；6h后将水加至高出试件顶面20mm以上，并再放置48h让其自由吸水。

这样逐次加水能使试件孔隙中的空气逐渐逸出。

(3)取出试件，用湿纱布擦去表面水分，立即称其质量m2(g)。

5.试验结果计算
按下列公式计算石料吸水率（精确至0.01%):
W,=m2-m1/m1×100%
式中：W,——石料吸水率（%);
m1——烘干至恒重时试件的质量（g);
m2——吸水至恒重时试件的质量（g)。

组织均匀的试件，取三个试件试验结果的平均值作为测定值；组织不均匀的，则取5m2个试件试验结果的平均值作为测定值。

塑胶水分测定仪的检测方法塑胶水分测定仪的基本介绍塑胶水分测定仪是一种用于测量塑料制品中含水量的仪器，它通过称重和烘烤的方式对样品中的水分进行检测。

塑胶制品的生产过程中，水分的含量对产品的质量和性能有着重要的影响。

如果塑料中的水分含量过高，将会在产品加工过程中产生气泡、气孔、崩边等不良现象，甚至会影响产品的强度、耐久性和使用寿命。

因此，对于塑料制品的生产过程中，进行水分检测是非常必要的。

检测原理塑胶水分测定仪的检测原理是通过称重和烘烤的方式来测量样品中的水分含量。

测量过程是先将待测样品称重，然后将其放入塑胶水分测定仪中进行烘烤。

在烘烤过程中，仪器会自动调节温度和湿度，使样品内的水分逐渐挥发出去。

当样品内的水分完全挥发后，仪器将会再次测量其重量，从而得出样品中的水分含量。

检测方法样品制备在进行检测之前，需要将待测样品进行制备。

具体步骤如下：1.确定待测样品的重量：将塑料样品放于天平上进行称重，记录下塑料样品重量。

2.选择待测样品数量：根据待测塑料制品的体积和质量，选择合适的样品数。

3.样品取样：将样品从不同角度位、不同位置取样，避免偏差。

4.样品加工：将样品取下后，使用刀子或剪刀进行加工，尽可能使样品成一定形状。

检测步骤1.打开塑胶水分测定仪：按照仪器使用手册的说明，打开塑胶水分测定仪并插入电源。

2.设置仪器参数：根据样品的性质和仪器的使用说明，设置仪器的温度和时间参数。

3.放置样品：将制备好的样品放入塑胶水分测定仪的称重托盘上，并确保样品的重量已记录。

4.启动检测：按下“开始”按钮，仪器便会开始烘烤样品。

5.检测完毕：当仪器完成烘烤后，按下停止按钮。

此时，仪器会自动测量样品的重量，并将结果显示在仪器屏幕上。

6.结果处理：根据仪器屏幕上的结果，计算出塑料制品中的水分含量。

具体计算公式为：Water content (%) = (W2 - W1) / W1 × 100%其中，W1代表原始样品重量，W2代表烘烤后样品的重量。

硬质泡沫塑料吸水率测定方法1.1体积吸水率1.1.1 适用范围及规范性引用文件1 适用范围本规程规定了硬质泡沫塑料吸水率的测定方法：通过测量浸没在水下50mm、96h后样品的浮力来测定。

本规程规定了样品体积变化的校正和样品切割表面泡孔的体积校正。

2规范性引用文件下列标准所包含的条文，通过在本规程中引用而构成为本规程的条文。

使用本规程的各方应探讨使用下列标准最新版本的可能性。

GBT 8810-2005 硬质泡沫塑料吸水率的测定GB/T 2918-1998 塑料试样状态调节和试验的标准环境GB/T 6342-1996 泡沫塑料与橡胶线性尺寸的测定1.1.2 设备仪器1 天平天平应能悬挂网笼，准确至0.1g。

2 网笼由不锈钢材料制成，大小能容纳试样，底部附有能抵消试样浮力的重块，顶部有能挂到天平上的挂架（见图1.1）。

图1.1 网笼及试块示意图3 圆筒容器直径至少为250mm，高为250mm。

4 低渗透塑料薄膜如聚乙烯薄膜。

5 切片器切片器应有切割样品薄片厚度为0.1mm~0.4mm的能力（见图10.2）。

图1.2 切片机6 载片将两片幻灯玻璃片用胶布粘接成活叶状，中间放一张印有标准刻度（长度30mm）的计算坐标的透明塑料薄片（见图1.3）。

图1.3 载片装置7 投影仪适用于50mm×50mm标准幻灯片的通用型35mm幻灯片投影仪，或者带有标准刻度的投影显微镜。

1.1.3 检测程序1 试验原理通过测量在蒸馏水中浸泡一定时间试样的浮力来测定材料的吸水率。

2 浸泡液选用蒸馏后至少放置48h后的蒸馏水。

3 检测步骤首先依次进行试验的基本步骤，包括如下内容：按GB/T 2918的规定调节试验环境为（23±2）℃和（50±5）%相对湿度；称量干燥后试样质量（m1），准确至0.1g；按GB/T6342的规定测量试样线性尺寸用于计算V0，V0准确至0.1cm3；在试验环境下将蒸馏水注入圆筒容器内；将网笼浸入水中，除去网笼表面气泡，挂在天平上，称其表观质量（m2），准确至0.1g；将试样装入网笼，重新浸入水中，并使试样顶面距水面约50mm，用软毛刷或搅动除去网笼和样品表面气泡；用低渗透塑料薄膜覆盖在圆筒容器内；（96±1）h或其他约定浸泡时间后，移去塑料薄膜，称量浸在水中装有试样的网笼的表观质量（m3），准确至0.1g；目测试样溶胀情况，来确定溶胀和切割表面体积的校正。

塑料吸水率测试标准塑料吸水率是指塑料材料在特定条件下吸收水分的能力，这一指标在塑料制品的生产和使用过程中具有重要意义。

塑料制品在实际使用中，如果吸水率过高，会导致产品变形、老化甚至失效，因此对塑料吸水率的测试标准十分重要。

一、测试方法。

塑料吸水率的测试方法通常采用称重法和浸水法。

其中，称重法是将干燥的样品称重，然后在特定条件下浸泡一段时间后再次称重，通过比较前后两次称重的差值计算吸水率；浸水法则是将样品完全浸入水中，一段时间后取出，擦干表面水分后称重，同样通过前后两次称重的差值计算吸水率。

二、测试条件。

在进行塑料吸水率测试时，需要控制一定的测试条件，以保证测试结果的准确性。

首先是温度和湿度条件，一般情况下，测试温度为23℃，湿度为50%RH；其次是测试时间，根据不同的塑料材料，测试时间一般在24小时至7天不等；最后是样品的制备和处理，需要保证样品的表面光滑、无气孔和裂纹，以及去除表面的杂质和残留水分。

三、测试数据处理。

在测试完塑料吸水率后，需要对测试数据进行处理和分析。

首先是计算吸水率的公式，吸水率（%）=（样品吸水后重量-干燥样品重量）/干燥样品重量×100%；其次是对测试数据进行统计分析，包括计算平均吸水率、标准偏差等参数，以及绘制吸水率随时间变化的曲线图，从而对塑料材料的吸水性能进行评估。

四、应用范围。

塑料吸水率测试标准适用于各类塑料材料，包括塑料片、塑料管、塑料棒等各种形状的塑料制品。

通过测试吸水率，可以评估塑料材料的吸水性能，为塑料制品的设计、生产和使用提供重要参考依据。

五、结论。

塑料吸水率测试标准是评估塑料材料吸水性能的重要手段，通过严格控制测试条件和数据处理方法，可以获得准确可靠的测试结果。

在实际应用中，可以根据测试结果对塑料制品的设计和材料选择进行优化，以提高产品的使用寿命和性能稳定性。

六、建议。

为了进一步规范塑料吸水率测试，提高测试结果的可比性和准确性，建议制定统一的测试标准和方法，明确测试条件和数据处理要求，以及对测试设备和人员进行资质认证和培训，从而推动塑料吸水率测试工作的标准化和规范化发展。

DISO62is technically equivalent to this test method.2.Referenced Documents2.1ASTM Standards:D647Practice for Design of Molds for Test Specimens of Plastic Molding Materials22.2ISO Standard:ISO62Plastics—Determination of Water Absorption33.Significance and Use3.1This test method for rate of water absorption has two chief functions:first,as a guide to the proportion of water absorbed by a material and consequently,in those cases where the relationships between moisture and electrical or mechanical properties,dimensions,or appearance have been determined, as a guide to the effects of exposure to water or humid conditions on such properties;and second,as a control test on the uniformity of a product.This second function is particu-larly applicable to sheet,rod,and tube arms when the test is made on thefinished product.3.2Comparison of water absorption values of various plas-tics can be made on the basis of values obtained in accordance with7.1and7.4.3.3Ideal diffusion of liquids4into polymers is a function of the square root of immersion time.Time to saturation is strongly dependent on specimen thickness.For example,Table 1shows the time to approximate time saturation for various thickness of nylon-6.3.4The moisture content of a plastic is very intimately related to such properties as electrical insulation resistance, dielectric losses,mechanical strength,appearance,and dimen-sions.The effect upon these properties of change in moisture content due to water absorption depends largely on the type of exposure(by immersion in water or by exposure to high humidity),shape of the part,and inherent properties of the plastic.With nonhomogeneous materials,such as laminated forms,the rate of water absorption may be widely different through each edge and surface.Even for otherwise homoge-neous materials,it may be slightly greater through cut edges than through molded surfaces.Consequently,attempts to correlate water absorption with the surface area must generally be limited to closely related materials and to similarly shaped specimens:For materials of widely varying density,relation between water-absorption values on a volume as well as a weight basis may need to be considered.4.Apparatus4.1Balance—An analytical balance capable of reading 0.0001g.4.2Oven,capable of maintaining uniform temperatures of 5063°C[12265.4°F]and of105to110°C[221to230°F].5.Test Specimen5.1The test specimen for molded plastics shall be in the form of a disk50.8mm[2in.]in diameter and3.2mm[1⁄8in.] in thickness(see Note2).Permissible variations in thickness are60.18mm[60.007in.]for hot-molded and60.30mm [60.012in.]for cold-molded or cast materials.1This test method is under the jurisdiction of ASTM Committee D20on Plasticsand is the direct responsibility of Subcommittee D20.50on Durability of Plastics.Current edition approved Nov.1,2005.Published January2006.Originally approved st previous edition approved in1998as D570-98.2Withdrawn.3Available from American National Standards Institute(ANSI),25W.43rd St., 4th Floor,New York,NY10036.4Additional information regarding diffusion of liquids in polymers can be found in the following references:(1)Diffusion,Mass Transfer in Fluid Systems,E.L.Cussler,Cambridge University Press,1985,ISBN0-521-29846-6,(2)Diffusion in Polymers,J.Crank and G.S.Park,Academic Press,1968,and(3)“Permeation, Diffusion,and Sorption of Gases and Vapors,”R.M.Felder and G.S.Huvard,in Methods of Experimental Physics,V ol16C,1980,Academic Press.1Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.N OTE 2—The disk mold prescribed in the Molds for Disk Test Specimens Section of Practice D 647is suitable for molding disk test specimens of thermosetting materials but not thermoplastic materials.5.2ISO Standard Specimen —The test specimen for homo-geneous plastics shall be 60by 60by 1mm.Tolerance for the 60-mm dimension is 62mm and 60.05mm for the 1-mm thickness.This test method and ISO 62are technically equiva-lent when the test specimen described in 5.2is used.5.3The test specimen for sheets shall be in the form of a bar 76.2mm [3in.]long by 25.4mm [1in.]wide by the thickness of the material.When comparison of absorption values with molded plastics is desired,specimens 3.2-mm [1⁄8-in.]thick should be used.Permissible variations in thickness shall be 0.20mm [60.008in.]except for materials which have greater standard commercial tolerances.5.4The test specimen for rods shall be 25.4-mm [1-in.]long for rods 25.4mm in diameter or under and 12.7-mm [1⁄2-in.]long for larger-diameter rods.The diameter of the specimen shall be the diameter of the finished rod.5.5The test specimen for tubes less than 76mm [3in.]in inside diameter shall be the full section of the tube and 25.4-mm [1-in.]long.For tubes 76mm [3in.]or more in inside diameter,a rectangular specimen shall be cut 76mm in length in the circumferential direction of the tube and 25.4mm in width lengthwise of the tube.5.6The test specimens for sheets,rods,and tubes shall be machined,sawed,or sheared from the sample so as to have smooth edges free from cracks.The cut edges shall be made smooth by finishing with No.0or finer sandpaper or emery cloth.Sawing,machining,and sandpapering operations shall be slow enough so that the material is not heated appreciably.N OTE 3—If there is any oil on the surface of the specimen when received or as a result of machining operations,wash the specimen with a cloth wet with gasoline to remove oil,wipe with a dry cloth,and allow to stand in air for 2h to permit evaporation of the gasoline.If gasoline attacks the plastic,use some suitable solvent or detergent that will evaporate within the 2-h period.5.7The dimensions listed in the following table for the various specimens shall be measured to the nearest 0.025mm [0.001in.].Dimensions not listed shall be measured within 0.8mm [61⁄32in.].Type of Specimen Dimensions to Be Measured to the Nearest 0.025mm [0.001in.]Molded disk thickness Sheet thicknessRod length and diameterTubeinside and outside diameter,and wall thickness6.Conditioning6.1Three specimens shall be conditioned as follows:6.1.1Specimens of materials whose water-absorption value would be appreciably affected by temperatures in the neigh-borhood of 110°C [230°F],shall be dried in an oven for 24h at 5063°C [12265.4°F],cooled in a desiccator,and imme-diately weighed to the nearest 0.001g.N OTE 4—If a static charge interferes with the weighing,lightly rub the surface of the specimens with a grounded conductor.6.1.2Specimens of materials,such as phenolic laminated plastics and other products whose water-absorption value has been shown not to be appreciably affected by temperatures up to 110°C [230°F],shall be dried in an oven for 1h at 105to 110°C [221to 230°F].6.1.3When data for comparison with absorption values for other plastics are desired,the specimens shall be dried in an oven for 24h at 5063°C [12265.4°F],cooled in a desic-cator,and immediately weighed to the nearest 0.001g.7.Procedure7.1Twenty-Four Hour Immersion —The conditioned speci-mens shall be placed in a container of distilled water main-tained at a temperature of 2361°C [73.461.8°F],and shall rest on edge and be entirely immersed.At the end of 24,+1⁄2,−0h,the specimens shall be removed from the water one at a time,all surface water wiped off with a dry cloth,and weighed to the nearest 0.001g immediately.If the specimen is 1⁄16in.or less in thickness,it shall be put in a weighing bottle immedi-ately after wiping and weighed in the bottle.7.2Two-Hour Immersion —For all thicknesses of materials having a relatively high rate of absorption,and for thin specimens of other materials which may show a significant weight increase in 2h,the specimens shall be tested as described in 7.1except that the time of immersion shall be reduced to 12064min.7.3Repeated Immersion —A specimen may be weighed to the nearest 0.001g after 2-h immersion,replaced in the water,and weighed again after 24h.N OTE 5—In using this test method the amount of water absorbed in 24h may be less than it would have been had the immersion not been interrupted.7.4Long-Term Immersion —To determine the total water absorbed when substantially saturated,the conditioned speci-mens shall be tested as described in 7.1except that at the end of 24h they shall be removed from the water,wiped free of surface moisture with a dry cloth,weighed to the nearest 0.001g immediately,and then replaced in the water.The weighings shall be repeated at the end of the first week and every two weeks thereafter until the increase in weight per two-week period,as shown by three consecutive weighings,averages less than 1%of the total increase in weight or 5mg,whichever is greater;the specimen shall then be considered substantially saturated.The difference between the substantially saturated weight and the dry weight shall be considered as the water absorbed when substantially saturated.7.5Two-Hour Boiling Water Immersion —The conditioned specimens shall be placed in a container of boiling distilled water,and shall be supported on edge and be entirely im-mersed.At the end of 12064min,the specimens shall be removed from the water and cooled in distilled water main-tained at room temperature.After 1561min,the specimens shall be removed from the water,one at a time,all surfaceTABLE 1Time to Saturation for Various Thickness of Nylon-6Thickness,mmTypical Time to 95%Saturation,h110024003.2100010100002562000water removed with a dry cloth,and the specimens weighed to the nearest0.001g immediately.If the specimen is1⁄16in.or less in thickness,it shall be weighed in a weighing bottle. 7.6One-Half-Hour Boiling Water Immersion—For all thicknesses of materials having a relatively high rate of absorption and for thin specimens of other materials which may show a significant weight increase in1⁄2h,the specimens shall be tested as described in7.5,except that the time of immersion shall be reduced to3061min.7.7Immersion at50°C—The conditioned specimens shall be tested as described in7.5,except that the time and temperature of immersion shall be4861h and5061°C [122.061.8°F],respectively,and cooling in water before weighing shall be omitted.7.8When data for comparison with absorption values for other plastics are desired,the24-h immersion procedure described in7.1and the equilibrium value determined in7.4 shall be used.8.Reconditioning8.1When materials are known or suspected to contain any appreciable amount of water-soluble ingredients,the speci-mens,after immersion,shall be weighed,and then recondi-tioned for the same time and temperature as used in the original drying period.They shall then be cooled in a desiccator and immediately reweighed.If the reconditioned weight is lower than the conditioned weight,the difference shall be considered as water-soluble matter lost during the immersion test.For such materials,the water-absorption value shall be taken as the sum of the increase in weight on immersion and of the weight of the water-soluble matter.9.Calculation and Report9.1The report shall include the values for each specimen and the average for the three specimens as follows:9.1.1Dimensions of the specimens before test,measured in accordance with5.6,and reported to the nearest0.025mm [0.001in.],9.1.2Conditioning time and temperature,9.1.3Immersion procedure used,9.1.4Time of immersion(long-term immersion procedure only),9.1.5Percentage increase in weight during immersion,cal-culated to the nearest0.01%as follows:Increase in weight,%5wet weight2conditioned weightconditioned weight31009.1.6Percentage of soluble matter lost during immersion,ifdetermined,calculated to the nearest0.01%as follows(seeNote6):Soluble matter lost,%5conditioned weight2reconditioned weightconditioned weight3100N OTE6—When the weight on reconditioning the specimen after im-mersion in water exceeds the conditioned weight prior to immersion,report“none”under9.1.6.9.1.7For long-term immersion procedure only,prepare agraph of the increase in weight as a function of the square rootof each immersion time.The initial slope of this graph isproportional to the diffusion constant of water in the plastic.The plateau region with little or no change in weight as afunction of the square root of immersion time represents thesaturation water content of the plastic.N OTE7—Deviation from the initial slope and plateau model indicatesthat simple diffusion may be a poor model for determining water content.In such cases,additional studies are suggested to determine a better modelfor water absorption.9.1.8The percentage of water absorbed,which is the sum ofthe values in9.1.5and9.1.6,and9.1.9Any observations as to warping,cracking,or changein appearance of the specimens.10.Precision and Bias510.1Precision—An interlaboratory test program was car-ried out using the procedure outlined in7.1,involving threelaboratories and three materials.Analysis of this data yields thefollowing coefficients of variation(average of three replicates).WithinLaboratoriesBetweenLaboratoriesAverage absorption above1%(2materials)2.33% 4.89%Average absorption below0.2%(1material)9.01%16.63%N OTE8—A round robin is currently under way to more completelydetermine repeatability and reproducibility of this test method.10.2Bias—No justifiable statement on the bias of this testmethod can be made,since the true value of the propertycannot be established by an accepted referee method.11.Keywords11.1absorption;immersion;plastics;water5Supporting data are available from ASTM Headquarters.Request RR:D20-1064.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed everyfive years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959, United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at610-832-9585(phone),610-832-9555(fax),or service@(e-mail);or through the ASTM website ().。

吸水率的测定方法一、吸水率测试方法1、准备五块石材，每块体积约为五十立方公分，先将尘土清除掉，等待其完全干燥，然后再称其重量。

2、重量获得后，再把它放在量筒、洗涤器或其他容器之内，用水淹至试样四分一的高度，浸二小时。

3、加水到试样二分一的高度，再浸三小时后；再加水淹到试样四分三的高度左右，直到试样完全被水淹没。

4、再令试样在水中放置二十四小时，然后取出，用布轻轻擦干并称量之，即可按下列公式将石材的吸水率求出：W=(B-G)/G×100%式中W为吸水率，以百分率表示，G为试样干燥后重量，以公克为单位，B为试样饱含水份以后的重量，公克作为基本单位。

二、吸水率与含水率区别1、材料在水中吸收水分到了饱和状态时，吸收水分的质量占材料干燥情况下质量的百分率为材料的吸水率。

对同一种材料，吸水率为固定值。

材料吸水率与材料的孔隙率和孔隙构造情况有密切的关系。

2、一般来说，密实材料或具有闭口孔隙的材料是不吸水的；具有粗大孔隙的材料因其水分不易留存，吸水率一般小于孔隙率；而孔隙率较大伴随有细小开口连通孔隙的亲水材料，吸水率较大。

材料吸收水分后，不仅表观密度增大、强度降低，保温和隔热的性能也降低，且更易受冰冻破坏，因此，材料吸水后对材质是不利的。

3、材料的含水率是指材料在空气中，含有水分的质量占材料干质量的百分率。

材料含水率的大小，除了与本身的性质，还与孔隙大小及构造有关，周围空气的温湿度也会影响。

含水率随着空气温湿度大小变化而做相应的变化，当空气湿度大温度低时，材料的含水率就增大，反之则小。

4、当材料的含水率与空气湿度相平衡时，其含水率称为平衡含水率，当材料吸水达到饱和状态时的含水率即为吸水率。

虽然说看得多不如做得多，但是不看也不知道吸水率的测试方法，通过上面的这些内容我们就能知道了。

塑料的水分含量的测定方法我折腾了好久塑料的水分含量的测定方法，总算找到点门道。

说实话，一开始我真是瞎摸索。

我最早就是想着把塑料拿出来直接在太阳下晒晒，看重量会不会减少来算水分，这想法现在想想挺傻的。

因为很多时候，塑料暴露在空气中或者在太阳下，它可能是既失水又吸进去其他东西，没法单纯判定就是水分减少了，结果很不准确。

后来我又想了个法子，就是拿个密封袋把塑料装起来，放个湿度计在里面，观察湿度变化。

但是这个湿度计只能反映密封袋里面空气湿度的变化，根本没法准确体现塑料自身水分含量到底是多少。

这算是又一次失败的尝试。

再之后我就开始找专业的测定方法。

我了解到有烘干法，这个方法就像是在给塑料做一场脱水运动。

就是把塑料放到一个专门的烘干箱里，设置好温度和时间，一般来说温度100多度，烘几个小时。

然后在烘之前称一下塑料的重量，烘之后再称一次，根据前后重量的差别来确定水分含量。

但这里头也有学问，比如说这个温度和时间，不同类型的塑料承受能力不一样。

像那种比较软的塑料，温度高了时间长了可能会变形融化，这样就会影响结果。

所以如果不确定塑料的类型，就需要先从比较低的温度和短时间开始尝试，再逐步调整。

我还试过用卡尔费休法。

这个方法那就更复杂点。

简单来说呢，是利用一个特殊的试剂和塑料里的水分发生反应，根据反应剂的消耗量来计算水分含量。

这里面试剂的调配和保存都得特别小心，因为试剂要是变质了，那整个结果就全错了。

我就有一次不小心，没盖好盛试剂容器的盖子，再做测定的时候，结果就乱套了，怎么算都不对。

从那次之后我就特别注意实验的细节，哪怕是一个小小的瓶盖。

还有一点啊，如果要测定大量塑料的水分含量的时候，取样一定要均匀。

我之前有一次没注意这一点，只取了表面的部分，结果测定出来的数据偏差特别大。

所以啊，从不同部位取少量塑料混合在一起作为样品，再进行测定就靠谱多了。

反正这个测定塑料水分含量啊，真得小心谨慎，不断尝试才能找到适合的方法。

塑料吸水率测试方法
1. 嘿，你知道吗？塑料吸水率测试方法之一就是浸泡法！就像把糖块扔进水里看它吸多少水一样。

拿个样品泡在水里一定时间，然后看它重量增加了多少，不就能知道吸水率啦！
2. 还有啊，真空法也是常见的塑料吸水率测试方法哦！这不就像用吸管吸水一样，把空气抽走，让水更顺畅地进入塑料里呀。

3. 还有一种方法是水煮法呢！就好比煮饺子，把塑料放水里煮一煮，再瞧瞧它吸了多少水。

这方法简单直接呀！
4. 另外，湿度法也不错哟！想象一下塑料处在一个潮湿的环境里，慢慢地吸收水分，就像我们在潮湿的天气里感觉身上黏糊糊的。

5. 称重法也是个好用的办法呀！不停地测塑料的重量，看着它一点点因为吸水而变化，多有意思！
6. 最后不得不提的是滴定法呢！感觉就像精确地给塑料喂水，然后准确地知道它喝了多少，真的很酷！我觉得啊，这些测试方法都各有特点，都能帮我们很好地了解塑料的吸水率呢！。