汽车用高分子材料：改性NR老化性能的TG分析

本文研究了热老化、酸老化和光老化对改性NR老化性能的影响.采用热量分析(TGA)计算了改性NR二个热失重阶段的热降解动力学参数,并从老化前后热稳定性,活化能和频率因子变化的角度分析老化程度的大小,结果表明,三种老化程度的顺序为:光老化>热老化>酸老化.     

汽车用有机玻璃(PMMA)老化性能的热重分析法(TGA)

本文研究了热老化、酸老化和光老化对PMMA老化性能的影响,采用热重分析(TG)计算了PMMA二个热失重阶段的热降解动力学参数,从老化前后热稳定性和活化能变化的角度分析老化的程度,结果表明:热老化比原来减轻,而其它二种老化(光老化和酸老化)比原来严重。     

国内外轮胎整胎老化测试研究

以轮胎老化测试为基础,重点介绍了国外轮胎市场上整胎的老化测试和实验室老化测试,探究实验室老化测试和实际老化之间的关联,提出用实验室老化来模拟实际老化的方法。     

聚乙烯材料的老化和耐候性研究进展

介绍了聚乙烯材料光氧老化和热氧老化的老化机理,综述了国内聚乙烯光氧老化、热氧老化和耐候性能的研究进展。通过对聚乙烯在室外环境中老化性能的研究,准确掌握了聚乙烯的老化性能,为聚乙烯寿命评估提供可靠的技术支持。     

氨纶老化性能影响因素的研究进展

综述了氨纶的老化影响因素研究,主要是紫外老化、湿热老化、氯水老化等。通过纤维分子结构、表面形态和氨纶合成方法方面推测了氨纶可能的老化机制,同时提出了改善氨纶老化性能的可行性方法。     

聚对苯二甲酸乙二醇酯老化研究进展

综述了近年来聚对苯二甲酸乙二醇酯(PET)老化行为的研究进展,分析了物理老化、热氧老化、光氧老化和湿热老化的作用机理,并提出了今后研究的方向。     

复合固体推进剂老化性能研究综述

从传统老化特征研究、化学老化特征研究和贮存寿命预估3个方面对复合固体推进剂老化性能的研究现状进行了综述。其中,传统老化特征研究包含力学老化特征、图像老化特征和组分含量老化特征3个方面,化学老化特征研究包含特征官能团测定、化学老化的分子模拟分析以及气体含量监测分析3个方面。同时从研究对象、老化特征提取、分子模拟分析和寿命预估模型无损性4个方面对推进剂老化性能的研究进行了总结与展望。     

缓冷玻璃态ABS在拉伸应变状态下的老化行为

用万能拉伸实验机和差示扫描量热仪(DSC)对物理老化和应变老化的ABS试样进行研究。力学性能测试结果表明:在相同老化时间内,应变老化试样的屈服应力和弹性模量高于物理老化试样,而断裂伸长率却小于物理老化试样。DSC测试表明:在相同老化时间内,应变老化试样比物理老化试样的热流吸收峰面积更大,说明应变老化试样形成了与物理老化试样不同的结构。     

聚合物的老化与稳定化

综述了各种环境因素对聚合物老化的影响,介绍了聚合物老化的主要机理,列出了老化机理研究的一些方法以及聚合物的防老化方法。     

高分子材料的老化研究

本文介绍了由高分子材料老化引起的外观、物理性能、力学性能、电性能的变化;分析了引起高分子材料老化的内在因素和外在因素,例如化学结构、物理形态、立体规整性、分子量及其分布情况、金属杂质、温度、湿度、氧气、光照、化学介质、生物等;阐述了自然环境老化实验、人工加速老化实验、耐候性实验、热老化实验、湿热老化实验、臭氧老化实验、盐雾腐蚀实验、耐寒性实验、抗霉实验等老化评价方法和物理性能、力学性能、微观分析、耐久性能以及系统分析技术等老化性能评价指标;并对热老化预防措施、湿热老化预防措施、氧老化预防措施、光老化预防措施以及生物老化预防措施进行了展望。     

氟改性丙烯酸酯对聚合物水泥基复合材料抗老化性能影响研究

分别对氟改性丙烯酸酯乳液和普通纯丙乳液为有机组分的聚合物水泥基复合材料进行紫外人工加速老化试验,并对其进行附着力、抗冲击性和抗弯折性测试。实验结果表明,氟改性丙烯酸酯较普通纯丙乳液拥有更好的抗老化性能。     

Effect of storage on ultraviolet irradiated HDPE

Abstract

Oxygen containing groups such as C=O and C–O were introduced onto high density polyethylene (HDPE) chains by ultraviolet (irradiated at 70°C and different light intensities in air). The contents of oxygen containing groups were unchanged after storage, indicating that these groups were stable in HDPE chains. The water contact angles of the irradiated HDPE at different light intensities after storage were equivalent to those of the irradiated HDPE before storage. Small quantity of the irradiated HDPE at different light intensities before and after storage as a compatibiliser were added into the HDPE/CaCO₃ composite respectively, and the HDPE/CaCO₃/irradiated HDPE before and after storage composite were prepared respectively. The tensile strength and the impact strength of HDPE/CaCO₃/irradiated HDPE after storage composite were similar to those of the HDPE/CaCO₃/irradiated HDPE before storage composite. The irradiated HDPE after storage was an efficacious compatibiliser.     

两类增韧HDPE的力学性能及熔体流动性

以高密度聚乙烯(HDPE)为基体树脂、(乙烯／丙烯)共聚物和丁苯橡胶为增韧剂制得增韧母料(E-TMB)。分别采用将E-TMB与HDPE热机械共混和将(乙烯／丙烯)共聚物、丁苯橡胶与HDPE简单共混的方法制备了HDPE／E-TMB及HDPE／弹性体两类增韧HDPE。结果表明,HDPE／E-TMB的悬臂梁缺口冲击强度的提高幅度、拉伸屈服应力保持率均显著优于HDPE／弹性体,二者的弯曲弹性模量保持率基本相同;HDPE／E-TMB的熔体流动速率比HDPE／弹性体的小,但仍适宜于注射成型和挤出成型。     

电子辐照HDPE对HDPE／PET的增容作用

通过用电子束辐照高密度聚乙烯(HDPE),引入极性基团到HDPE中,增加了HDPE与聚对苯二甲酸乙二醇酯(PET)共混体系的相容性。辐照的HDPE与PET共混,使共混转矩和比能量消耗增加;但HDPE辐照一个月后再与PET共混,则使共混转矩和比能量消耗降低。力学性能数据表明,辐照的HDPE对HDPE/PET共混体系具有增容作用。     

The reaction of boric acid with wood in a polystyrene matrix

To improve the physical properties of starch-filled polyolefin, starch was modified into more hydrophobic material by the introduction of cholesterol unit, and the different starch-compositioned high-density polyethlene (HDPE) films were prepared with addition of either native starch or modified starch to compare their physical properties. The addition of either native starch or modified starch resulted in decreased crystallinities in all the different composite films containing starch. Interestingly, HDPE-blown films containing more than 10% native starch (HDPE/ST) showed a steeper decrease in crystallinity than correspondent HDPE containing the modified starch (HDPE/MS). Improvement of the dispersion and adhesion in HDPE/MS and HDPE/ST were also observed; but at high starch content, the HDPE/MS films showed higher tensile strength and elongation than the HDPE/ST. The degradation of HDPE/MS films in active sludge condition was much faster than that of the HDPE/ST films, although the degradation rate of HDPE/MS films in α-amylase condition were slower than the one of HDPE/ST films. © 1996 John Wiley & Sons, Inc.     

HDPE焊接三通管件壁厚数值优化设计

输气焊接HDPE三通管道,由于焊接使材料性能下降,并产生应力集中,因此必须对管道连接处增加壁厚.基于对HDPE材料性能和焊接处HDPE材料拉伸强度的试验,对HDPE材料三通管道壁厚进行数值优化设计.有限元模型中采用理想弹塑性和Ramberg-Osgood两种材料本构模型,计算得到管道等应力线以及壁厚优化曲线,对管道设计具有实际意义.     

电子束辐照HDPE及其与绢英粉共混体系流变行为的研究

采用高压毛细管流变仪及HDAKE转矩流变仪对辐照HDPE（e-HDPE）及其与绢英粉（STC）共混体系的流变行为进行了研究。结果表明：由于电子束辐照引起HDPE发生氧化降解，因此表观粘度和混炼转矩降低；与HDPE／STC共混体系相比，e-HDPE/STC体系的表观粘度和混炼矩也降低，加工性能得到改善。     

高流动性等规聚丙烯与高密度聚乙烯共混改性

研究了高密度聚乙烯（ HDPE ）含量对等规高流动性聚丙烯（ iPP ）力学性能和流动性能的影响。研究表明,随着HDPE含量的增大,冲击强度越来越大,硬度越来越小。 HDPE含量为10％时,拉伸/屈服强度以及弯曲强度出现最大值。共混体系的流动性能随着HDPE含量的增大而减小。     

高密度聚乙烯／尼龙1010共混体系的研究

采用接枝共聚方法,合成了高密度聚乙烯与马来酸酐,甲基丙烯酸和丙烯酸丁酯的接枝共聚物增容剂,研究了增容剂中接枝单体的种类及含量和增容剂用量等因素对高密度聚乙烯／尼龙1010共混体系力学性能的影响,结果表明在不同类型的接枝共聚物中以聚乙烯马来酸酐接枝共聚物对HDPE／PA1010共混体系的增容效果最好,在接枝单体含量和增容剂用量分别为4％－6％和5％左右时,共混体系的力学性能最好。     

Studies on fast functionalization of HDPE by ultraviolet irradiation and functionalized HDPE/CaCO3 composites

High density polyethylene (HDPE) was functionalized quickly by ultraviolet irradiated in ozone atmosphere. The oxygen-containing groups in the functionalized HDPE were C=O and C–O, and their content increased with increasing the irradiation time. The molecular weight of the functionalized HDPE decreased and its distribution became wider with increasing the irradiation time. The gel was not found in the functionalized HDPE. Compared with those of HDPE, the melting temperature and crystallinity of the functionalized HDPE decreased. With increasing the irradiation time, the hydrophilicity of the functionalized HDPE was enhanced, while its temperature of thermal decomposition decreased. The functionalized HDPE/CaCO₃ composites were prepared. Compared with those of HDPE/CaCO₃ composites, the compatibility and dispersion of the functionalized HDPE/CaCO₃ composites were enhanced observably. The tensile strength and notch impact strength of the functionalized HDPE/CaCO₃ composites increased with increasing the irradiation time.