吸水膨胀型PVC/CM TPV的结构及性能

以交联聚丙烯酸钠(PAAS)为吸水材料,通过动态硫化法制备了聚氯乙烯(PVC)/氯化聚乙烯橡胶(CM)热塑性硫化胶(TPV),并对其力学性能、微观相态结构及吸水行为进行了研究。结果表明,在实验范围内,PVC/PAAS/CM TPV呈现出典型弹性体软而韧的应力-应变行为。当PVC/PAAS/CM的共混比为30/60/70时,TPV表现出了良好的综合性能,在室温条件下的蒸馏水中浸渍200h,吸水膨胀率可达2 000%,且在吸水100h时,吸水速率出现了峰值,干燥后的TPV几乎无失重。由试样的显微镜照片可见,PAAS在基体中实现了均匀分散,PVC/PAAS/CM TPV的拉伸断裂面较粗糙,PAAS颗粒的较大尺寸及较低的界面结合导致了TPV的较低力学性能。     

CM/EVA热塑性硫化胶制备工艺与性能的研究

采用HAAKE转矩流变仪制备了氯化聚乙烯橡胶(CM)/乙烯-醋酸乙烯共聚物(EVA)热塑性硫化胶(TPV),研究了初始加工温度、转速以及动态硫化时间对共混物物理力学性能、流变行为以及动态力学性能的影响。结果表明:初始加工温度为150℃、转速60 r/min、动态硫化时间13 min时TPV的综合性能最好;橡胶加工分析仪(RPA)的研究表明,在没有填料加入的情况下共混物呈现出明显的Payne效应。返炼实验表明:通过此种工艺制备的CM/EVA为性能稳定的TPV。     

动态硫化丁腈橡胶/聚丙烯热塑性弹性体的耐油性能

研究了不同相容剂、硫化体系、增塑剂以及成型温度对动态硫化丁腈橡胶／聚丙烯热塑性弹性体(NBR／PPTPV)耐油性能的影响。结果表明,当端氨基液体丁腈橡胶(ATBN)为5份,马来酸酐接枝聚丙烯(MP)为10份时,ATBN／MP增容的TPV具有优异的耐油性能;酚醛树脂硫化TPV的耐油性能比过氧化二异丙苯(DCP)、溴化树脂硫化的TPV都要优越;聚酯增塑TPV的耐油性能优于邻苯二甲酸二辛酯(DOP)增塑的TPV;热成型温度对TPV的耐油性能影响不大。     

ZDMA补强PLA/NBR TPV的形态演变研究

采用动态硫化法制备了甲基丙烯酸锌(ZDMA)补强聚乳酸(PLA)/丁腈橡胶(NBR)热塑性硫化胶(TPV);采用邻苯二甲酸二辛酯(DOP)对其进行增塑,考察了ZDMA用量对TPV力学性能的影响;通过场发射扫描电子显微镜(FE-SEM)研究了动态硫化过程中橡胶相的形态演变。结果表明,在橡胶相中填充ZDMA可使TPV拉伸强度和撕裂强度提高;随着动态硫化反应的进行,NBR发生交联,同时增大了与树脂相的粘度差,并形成了独特的双连续相结构;随着动态硫化时间的延长,2相尺寸均明显减小。     

炭黑增强EVA/CMTPV的性能研究

以炭黑作补强剂,采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/氯化聚乙烯(CM)热塑性硫化胶(TPV),并研究了力学性能、Mullins效应和微观相结构。结果表明,当EVA/CM/CB质量比在40/60/6~40/60/24范围内时,TPV动态硫化产物表现出良好的综合性能。单轴循环拉伸实验表明,TPV存在明显的Mullins效应,即第1次拉伸后就表现出明显的应力软化现象;在拉伸比固定不变时,TPV最大应力随拉伸次数的增加而下降,残留应变逐渐增大。SEM观察结果表明,动态硫化EVA/CM/CB TPV的拉伸断面较为平坦,表现出良好的弹性回复能力,刻蚀样品表面均匀分散着CM硫化胶粒子,其平均尺寸为2μm左右。     

高抗冲聚苯乙烯/丁苯橡胶热塑性硫化胶的Payne效应及模型拟合

采用动态硫化法制备了高抗冲聚苯乙烯(HIPS)/丁苯橡胶(SBR)热塑性硫化胶(TPV)及苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)增容HIPS/SBR TPV,通过橡胶加工分析仪研究了TPV的Payne效应,并利用Kraus模型进行了拟合。结果表明,在相同应变下,随着HIPS/SBR TPV中HIPS含量的增加,TPV的储能模量(G')和损耗模量(G″)均增大;在不同测试温度条件下,随着应变的增加,纯SBR硫化胶的G'及G″变化不大,未出现Payne效应,HIPS/SBR TPV及SBS增容HIPS/SBR TPV均呈现明显的Payne效应;在应变测试范围内,利用Kraus模型对HIPS/SBR TPV及SBS增容HIPS/SBR TPV的G'拟合较好,但不能对G″有效拟合;提高测试温度,HIPS/SBR TPV及SBS增容HIPS/SBR TPV的小应变下G'初始值与大应变下Payne效应终止时G'值降低,G″达到最大值时的应变振幅特征值增大。     

炭黑增强SBR/EVA/HIPS热塑性硫化胶的性能研究

采用动态硫化法制备了炭黑增强丁苯橡胶(SBR)/乙烯-醋酸乙烯共聚物(EVA)/高抗冲聚苯乙烯(HIPS)热塑性硫化胶(TPV),研究了炭黑对TPV应力松弛及粘弹行为和力学性能的影响。结果表明,在TPV分散相SBR中加入炭黑,力学性能显著改善,应力松弛残留应力增大;频率扫描模式下,储能模量下降,损耗因子增加;应变扫描模式下,TPV表现出明显的Payne效应,且炭黑填充使Payne效应弱化。     

动态硫化PVC/CM热塑性弹性体的制备及性能

采用动态硫化法制备了聚氯乙烯(PVC)/氯化聚乙烯(CM)热塑性弹性体(TPE),并对其力学性能和微观相结构进行了研究。结果表明,动态硫化PVC/CM型TPE的拉伸强度及撕裂强度均随PVC含量的增加而提高,当PVC质量分数低于40%时,其应力-应变曲线呈现出典型的弹性体特征;PVC/CM的共混比为60/40时,所制备的TPE表现出了良好的综合性能;CM分散相粒径在10μm以下且较均匀地分散于PVC基体中。     

NBR/PVC TPV与NBR/PVC共混胶的性能对比研究

以丁腈橡胶(NBR)和聚氯乙烯(PVC)树脂为基础材料,采用动态硫化和熔融共混的方法分别制备了NBR/PVC动态硫化热塑性弹性体(TPV)与NBR/PVC共混胶,并对TPV和共混胶的高温拉伸性、耐热空气老化性、耐油性以及动态力学性能进行了对比研究。研究结果表明,室温下,NBR/PVC TPV的拉伸强度高于共混胶的;温度高于50℃时,共混胶的拉伸强度则高于TPV的。在测试温度下,NBR/PVC TPV的断裂伸长率始终低于共混胶,两种材料在120℃时都失去使用价值。NBR/PVC TPV的耐热空气老化性能和耐3#标准油性能优于NBR/PVC共混胶的。NBR/PVC TPV初始弹性模量较高,共混胶的损耗因子峰值高于TPV的,两种材料损耗因子峰值温度基本相同。     

ZDMA补强EVA/CPE/NBR共混型热塑性硫化胶的Payne和Mullins效应研究

采用动态硫化法制备乙烯-醋酸乙烯酯共聚物(EVA)/氯化聚乙烯(CPE)/丁腈橡胶(NBR)共混型热塑性硫化胶(TPV),研究TPV的应力-应变行为、微观相结构、Payne和Mullins效应。结果表明:甲基丙烯酸锌(ZDMA)补强TPV的储能模量随应变的增大而显著下降,表现出典型的Payne效应;TPV存在明显的Mullins效应,相同拉伸比下,与EVA/CPE/NBR TPV相比,ZDMA补强TPV的最大应力、瞬时残余应变、内耗、损耗因子和软化因子均有所提高。     

聚氯乙烯/氯化聚氯乙烯合金的性能研究

选择氯化聚氯乙烯(CPVC)、聚氯乙烯(PVC)为主体材料,研究了PVC/CPVC共混比、填料品种及用量等对PVC/CPVC合金体系力学性能的影响,同时利用扫描电镜对PVC/CPVC合金的微观结构进行了分析。结果表明,CPVC在加工过程中易发生脱HCl反应,PVC常用的铅盐稳定剂、有机锡类稳定剂均适于CPVC体系,且铅盐稳定剂的稳定效果要优于有机锡类稳定剂。当m(PVC)∶m(CPVC)从100∶0向70∶30变化时,随着CPVC含量的增多,PVC/CPVC二元合金体系的屈服强度、拉伸强度、弯曲强度、热变形温度(最大弯曲正应力分别为1.82 MPa和0.45 MPa)等均呈递增趋势,而冲击强度、断裂伸长率出现递减趋势。在填料用量为5份时,PVC/CPVC合金体系的力学性能以选用活性碳酸钙(CaCO3)为最佳。随着活性CaCO3用量的增加,PVC/CPVC合金的拉伸强度、弯曲强度、断裂伸长率呈先上升后下降的趋势。活性CaCO3用量的变化对冲击强度几乎无影响。当活性CaCO3用量超过10份时,PVC/CPVC合金的热变形温度上升。     

本体法聚氯乙烯的加工

介绍了本体法聚氯乙烯的加工工艺。该工艺完全可以采用悬浮法PVC的加工装置进行加工。而且加工容易、产品质量好、成本低、效益显著。     

Properties of chlorinated polyvinyl chloride

By chlorination of polyvinyl chloride in a water suspension, a number of samples of chlorinated polyvinyl chloride of varied chlorine content were prepared. The density, the temperature dependence of the dynamic modulus G' and the loss factor tg δ, as well as some mechanical properties of these samples were measured. The structure of the chlorinated PVC is discussed and the assumption expressed that the secondary maximum at ? 10°C corresponds to the movements of the short chain interceptions of poly (1,2-dichloroethylene). The tensile strength and flexural strength is growing linearly with the chlorine content. The impact strength from 65% Cl on is violently decreasing. By its behaviour, chlorinated polyvinyl chloride resembles a random copolymer of vinyl chloride and 1,2-dichloroethylene.     

氯化聚氯乙烯树脂综述

介绍了氯化聚氯乙烯树脂(CPVC)的性能、应用领域、生产和使用情况,分析了国内外CPVC树脂的性能差距及缩小其差距应采取的措施.     

Use of polyvinyl alcohol in the manufacture of polyvinyl chloride

The stabiliser used in the suspension polymerisation of vinylchloride influences greatly the quality of the resulting polyvinyl chloride, in particle size and distribution, and the absorption rate of plasticiser, etc. The relationship between the manufacturing conditions of polyvinylalcohol (PV-OH) and its dispersing power was studied using vinyl acetate and trichloro-ethylene in place of vinyl chloride monomer. It was found that the dispersing power increased with greater the blocklike distribution of the intramolecular residual acetyl group and uneven distribution of the intermolecular residual acetyl groups of PV-OH. When such PV-OH was used in suspension polymerisation of vinyl-chloride monomer, good quality polyvinylchloride was obtained. PV-OH with such characteristics is preferable as stabiliser for the suspension polymerisation of vinyl chloride monomer.     

Thermal decomposition products of polyvinyl chloride

When plastics are involved in a fire they may yield toxic decomposition products. Some quantitative data on the decomposition products of plastics are available in the literature, but it is difficult to assess the danger from the different amounts of various products because of the absence of a suitable method of evaluation. The authors have proposed a method of evaluation based on pyrolysis followed by gas chromatographic analysis and have used it to assess toxicity from various thermal decomposition products of polyvinyl chloride. Hydrogen chloride was found to be the main toxic decomposition product.     

Processing aids for chlorinated polyvinyl chloride

Comparative studies of melt processability showed that chlorinated polyvinyl chloride (CPVC) had low melt index and high Brabender melt temperature and torque, as compared with conventional rigid polyvinyl chloride (PVC). Of 3 processing aids at 10 percent concentration, triphenyl phosphate increased melt index 30-fold, fusion rate 10-fold, melt temperature 20°C, and torque 31 percent in CPVC. Two other processing aids, an acrylic and a styrene/acrylonitrile copolymer, were less effective. Improvements in PVC were less dramatic than in CPVC. Overall, use of processing aids made CPVC processability equal or even superior to conventional rigid PVC.