Measurement of residual stresses in injection‐molded polymer parts by time‐resolved fluorescence

Time‐resolved fluorescence properties of 9‐methylanthracene (9MAn) dispersed in film of polyvinylchloride (PVC) containing carbon black were studied under tensile loadings. The fluorescence lifetime of 9MAn decreased from 5.70 to 5.55 ns, whereas the stresses acting on the films increased from 0 to 3 MPa. The change in fluorescence lifetimes of 9MAn during the stress relaxation process showed that the fluorescence lifetimes were correlated with the stresses, not with the strains. The results suggest that 9MAn is a useful probe for monitoring stresses acting on the matrix. With the use of the fluorescence properties of 9MAn, the residual tensile stresses on the skin‐layer of PVC injection‐molded test pieces were estimated. The estimated residual stresses were about ～ 1 MPa. The residual stresses were relaxed to 0 MPa with annealing at 100°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2600–2603, 2002     

21世纪PVC工业的发展趋势

介绍ＰＶＣ工业概貌和面临的主要矛盾及其析技术开发前景：展望２１世纪的趋势，提出与石化工业“联营”，交进后十年的制胜战略。     

紫外光辐照交联聚氯乙烯的研究

研究了聚氯乙烯(PVC)在增塑剂邻苯二甲酸二辛酯(DOP)存在的情况下,以二苯甲酮(BP)为光敏剂、三丙烯酸三羟甲基丙烷酯(TMPTA)为交联剂的紫外光辐照交联。实验证明:光敏剂对交联有着显著的影响;经过辐照,可大幅度提高PVC制品的硬度及拉伸强度。     

动态硫化聚氯乙烯／再生胶／硫化胶粉共混型热塑性弹性体的研制

对聚氯乙烯（ＰＶＣ）／再生胶（ＲＲ）／硫化胶粉（ＶＲＰ）共混型热塑性体的配方和加工工艺进行了研究。结果表明,在１６０￣１７０℃条件下,采用二阶一段动态硫化法制成的热塑性弹性体,其拉抻强度为８．２ＭＰａ,扯断伸长为２９０％,邵尔Ａ型硬度为７０．５±５,撕裂强度为４３ｋＮ／ｍ Ｂｒａｂｅｎｄｅｒ Ｇａｒｖｅｙ口型挤出均得到了外观较好的挤出物,共混物的热塑性级别为４级。     

改性材料CPVC及TPVC等材料简介

本文就国内外ＰＶＣ改性材料ＣＰＶＣ的生产的现状,性能及用途作了较详细的介绍,并对其他改性ＰＶＣ材料作了简介。     

低发泡RPVC挤出成型的配方和工艺研究

提出了低发泡硬质聚氯乙烯挤出成型的配方和工艺。研究了稳定型,改性剂等配方因素对制品密度、表面、泡孔结构的影响,并讨论了制品密度与挤出工艺的关系。     

Tensile test of poly(vinyl chloride) filled with ground calcium carbonate particles

The fracture behavior of poly(vinyl chloride) filled with ground calcium carbonate particles during a tensile test was studied. The particles were prepared by crushing natural raw crystalline limestone. For this purpose, 10–50 parts of the particles having two different mean sizes (2 and 8 μm) without further surface treatment were mixed with 100 parts of poly(vinyl chloride) and 3 parts of lead stearate as a stabilizer using a mixing roll. A tensile test was carried out using a dumbbell specimen. As a result, the yield stress decreased with increase in the particle content; however, there was no significant influence of particle size. From scanning electron microscopic observations of the specimen's surfaces during the tensile test, it was found that the particle/matrix interfaces were delaminated and formed voids around the particles when the applied stress approached the yield stress, that is, the particles acted as voids and the matrix around the voids was plastically deformed effectively. These observations appear to be the reason for the decrease of yield stress by the incorporation of the particles. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 311–316, 1998     

Preparation and characterization of polyvinylchloride membrane embedded with Cu nanoparticles for electrochemical oxidation in direct methanol fuel cell

Copper nanoparticles were prepared by the chemical reduction method. These copper particles were embedded into the polyvinylchloride (PVC) matrix as support and used as an electrode (PVC/Cu) for the oxidation of methanol fuel for improving the current response. The PVC/Cu electrodes were characterized by thermal gravimetric analysis (TGA) for thermal stability of the electrode, X-ray diffraction (XRD) for identification of copper nanoparticles in the electrode, Fourier transform infrared spectroscopy (FTIR) to identify the interaction between PVC and Cu and scan electron microscopy (SEM) with EDAX for the morphology of the electrode. The electrocatalytic activity of the electrode was characterized by the cyclic voltammetry, linear sweep voltammetry, and chronoamperometry techniques. An increase in the electrode activity was observed with the increase of copper quantity from 0.18 g (PVC/Cu-0.18 g) to 0.24 g (PVC/Cu-0.24 g) and the maximum was found at 0.24 g of copper in the electrode. Also, it was observed that the electrode achieved the maximum catalytic current in 0.5 mol/L CH₃OH + 1 mol/L NaOH solution. FTIR identified that water molecules, C—H group, copper nanoparticle and its oxide were available in the electrode. SEM images with EDAX showed that copper particles were properly embedded in the polyvinylchloride matrix.     

PVC专用树脂的现状与研究进展

与普通PVC树脂相比,消光PVC树脂具有更好的耐溶剂性和耐热性,其制品在外力作用下有较小的永久形变,加工尺寸稳定性好;高抗冲PVC树脂提高了制品的冲击强度和加工性能;耐热PVC树脂具有更好的耐热、耐溶剂、力学性能和加工尺寸稳定性;超高聚合度PVC具有较长的使用寿命,良好的抗撕裂性能;超低聚合度PVC树脂吸油能力强、熔融黏度低、塑化时间短,可显著改进硬制品的抗冲击性能。PVC树脂的研究和开发应朝着精细化、功能化、系列化的方向发展。     

表面修饰纳米SiO2增强增韧聚氯乙烯

用过量的2 , 4-甲苯二异氰酸酯(TDI)对纳米SiO₂表面进行修饰合成含—NCO 的功能化SiO_2,再用丙烯酸羟丙酯(HPA)对其表面进行修饰合成出HPA修饰纳米SiO₂(SiO₂-HPA)。用共混法制备了SiO₂-HPA/PVC纳米复合材料,研究了不同 SiO₂含量及不同界面特性时复合材料的力学性能。结果表明: SiO₂-HPA/PVC复合材料的力学性能和加工性能等方面均优于未修饰的样品。在纳米SiO₂质量分数为0%～5%时,SiO₂-HPA/PVC的拉伸强度和冲击强度随着填充量的增加呈先上升后下降的趋势并在3%～4%达到最大值。表面修饰纳米SiO₂与PVC基体之间具有很强的界面结合作用,其相容性得到大大改善,填充表面修饰纳米SiO₂达到了增强增韧双重效果。此外,对纳米粒子增强增韧机制进行了深入的探讨。