影响汽车保险杠专用料PP SP179冲击强度测试结果的因素

分析了影响汽车保险杠专用料聚丙(烯PPS)P179悬臂梁缺口冲击强度测试结果的因素。结果表明:制样工艺不合理导致结果的偏差增大;制备缺口的相对刀速过大或过小都会导致测试结果偏低;刀刃质量差导致冲击强度偏低;在合理的制样工艺下,试样在缺口加工后只需调节4 h便可进行测试;试验仪器对结果也有一定影响需,定期进行检验。     

不同制样方法对塑料悬臂梁缺口冲击强度的影响

在测试聚乙烯产品的悬臂梁缺口冲击强度时,发现采用压塑法和注塑法制得的样条测试结果有较大区别,本文就两种不同制样方法引起聚乙烯产品冲击强度变化的原因进行分析,认为制样对结晶尺寸和分子的取向性的影响是造成强度变化的原因。     

制样方式及注塑工艺对聚酰胺6抗冲击性能的影响

通过改变注塑压力、注塑速度、模具温度、注塑温度等注塑成型工艺参数,研究了两种制样方式对改性聚酰胺(PA)6抗冲击性能的影响.结果表明:相同注塑成型工艺条件下,自带缺口试样的冲击强度都高于自制缺口的试样;注塑压力和注塑速度对自带缺口试样的冲击强度影响较大,但对自制缺口试样的冲击强度影响不大;模具温度和注塑温度对两种制样方...     

丙烯腈-丁二烯-苯乙烯共聚物缺口试样悬臂梁冲击强度研究

通过改变不同的测试条件,对丙烯腈-丁二烯-苯乙烯共聚物(ABS树脂)缺口试样悬臂梁冲击强度测试结果的影响因素进行了对比和分析,发现试样在状态调节与铣缺口操作先后顺序条件下的状态调节时间、铣缺口的工艺和不同摆锤能量对ABS树脂缺口试样悬臂梁冲击强度测试值影响不大,试样缺口中心相对台钳平面距离是影响ABS树脂缺口试样悬臂梁冲击强度测试值的主要因素。     

不同老化处理条件对HIPS水平燃烧速率的影响研究

在常温封闭放置、常温开放放置、60℃热氧处理、60℃/85%湿度湿热处理和60℃烘箱样条浸水处理等五种老化条件下,研究高抗冲聚苯乙烯(HIPS)的含水量、拉伸强度、悬臂梁缺口冲击强度和水平燃烧速率随处理时间的变化情况。结果发现,HIPS的刚性主要受处理环境温度的影响,经过高温处理的样品,拉伸强度明显升高。HIPS的缺口冲击强度与样条的含水量相关:若含水量高,则缺口冲击强度较高。HIPS的水平燃烧速率受含水量的影响较大:含水量降低,水平燃烧速率减缓,处理1 000 h仍保持HB40级别;含水量升高,由于水的增塑作用和氧化性,随着处理时间的延长,水平燃烧速率加快,达不到HB40级别。     

冲击改性剂对无卤阻燃聚苯乙烯的力学及阻燃性能影响

研究微胶囊红磷(MRP)和聚苯醚(PPO)复合阻燃剂对高抗冲聚苯乙烯(HIPS)材料力学性能的影响,并用抗冲击改性剂SBS及SEBS对高抗冲聚笨乙烯(HIPS)/微胶囊红磷(MRP)/聚苯醚(PPO)无卤阻燃材料的抗冲击性能和阻燃性能进行优化.结果表明:MRP和PPO的加入均会使HIPS体系的冲击性能下降,抗冲击改性剂SBS及SEBS 的加入改善了无卤阻燃HIPS的悬臂梁冲击强度,且对材料的阻燃性没有影响,制得增韧改性后的无卤阻燃HIPS材料具有优异的阻燃和力学等综合性能.     

双预聚釜工艺在高抗冲聚苯乙烯生产中的应用

阐述了高抗冲聚苯乙烯(HIPS)的抗冲击性能改善的原理,提出工艺流程优化改造的思路。结果表明:将原Fina工艺的单预聚釜改造为双预聚釜,调整2个预聚釜的工艺参数,控制第一预聚釜负荷在10%、第二预聚釜负荷在30%左右,可有效提高聚丁二烯接枝苯乙烯的接枝率;新调控技术投用后,HIPS的悬臂梁缺口冲击强度、拉伸强度提升了10%～20%。     

一次铣削12个试样的塑料制样机

据“British Plastics＆Rubber，2007，（April）：32”报道，德国Zwick公司开发出新型塑料试片缺口铣削（制样）机ZNO，按照ISO179-1标准（简支梁冲击强度）、ISO180或ASTM D256标准（悬臂梁冲击强度）制备塑料缺口试样，最多一次动作能制备12个试样。     

PP编织袋回收技术研究

研究了苯乙烯 丁二烯嵌段共聚物 (SBS)、苯乙烯 异戊二烯 苯乙烯接枝共聚物(SIS)、乙烯 丙烯酸或丙烯酸酯共聚物 (EAA)、乙烯 醋酸乙烯共聚物 (EVA)和乙烯 辛烯共聚物 (POE)几种聚烯增韧剂对废聚丙烯 (PP)编织袋回收料的改性效果。研究结果表明 ,当增韧剂加入量为 1 1份时 ,SIS的增韧效果最好 ,悬臂梁缺口抗冲击强度为1 3 4kJ/m2 ,比新鲜无规共聚PP1 3 3 0的缺口抗冲击强度 1 0 8kJ/m2 还高 ;EAA最低 ,其缺口抗冲击强度还不到均聚PP1 3 0 0的缺口抗冲击强度 5 8kJ/m2 ;其它几种增韧材料的抗冲击强度在 1 3 0 0和 1 3 3 0之间 ,当用量达到 2 0份时 ,其抗冲击强度迅速增加 ,达到 1 5 2kJ/m2 的最高值     

聚苯乙烯的抗冲击改进

针对纯聚苯乙烯的抗冲击强度太差,采用固体聚苯乙烯和橡胶机械掺合、将橡胶掺进聚苯乙烯的乳浊液中和将橡胶加在苯乙烯单体的溶液中进行聚合来改进抗冲击强度。对聚苯乙烯的工艺流程的装置作出系统的归纳和苯乙烯聚合的抗冲击进行改进的研究,使得橡胶粒子能更好的吸收冲击能和防止裂缝增长,从而改进了聚苯乙烯的抗冲击强度,最终可以制得抗冲击强度高的产品。     

ABS熔体加工稳定化的研究

针对复合稳定剂汽巴GX2921、1035／PS-1／119FL、1035／PS-1／KY500对ABS加工稳定化技术的研究。实验结果表明：选用合适的稳定体系,在260℃高温条件下加工ABS,材料的悬臂梁冲击性能保持率80％以上,色差ΔE保持3．0以内。     

Izod impact strength of a product molded of poly(vinyl chloride)/impact modifier containing voids (void MOD)

The Izod impact strength of a PVC (polyvinylchloride)/MOD (impact modifier) molded product was investigated by suitably reducing the amount of crosslinking agent in the rubber of MOD or by making rubber particles void when they were in the form of a latex. As a result, (1) when the amount of crosslinking agent in rubber was suitably reduced, the Izod impact strength of the PVC/MOD molded product was improved in both ordinary MOD and void MOD. However, with the extremely small amount of crosslinking agent, low Izod impact strength was exhibited. With the same amount of crosslinking agent, the void MOD showed higher Izod impact strength than the ordinary MOD. (2) SEM (scanning electron microscope) and TEM (transmission electron microscope) observations on the broken surface revealed that shear yield and crazing occurred in a whitened portion, and crazing was observed only near the surface of the broken section in a non‐whitened portion. It was also found that when the crosslinking degree of rubber was reduce, cavitations were liable to be formed in rubber under stress and expanded under rubber stress in the void MOD mor‐; than in the ordinary MOD. (3) As a result of a tensile test on the molded product, it was found that the void MOD caused lower yield stress than the ordinary MOD, thereby increasing in stress concentration. (4) P'rom these results, an estimation was earned out of the mechanism of improvement in the Izod impact strength of the MOD or void MOD using rubber with an appropriately lowered crosslinking degree.     

酞侧基聚芳醚砜／聚苯硫醚共混物的断裂韧性

本文通过有缺口和无缺口冲击试验、断裂韧性测试以及结合扫描电镜分析断面形貌，研究了酞侧基聚芳醚砜／聚苯硫醚共混物的断裂行为，讨论了聚苯硫醚增韧聚芳醚砜的机理。结果表明，共混物冲击强度的改善主要是由于其裂纹引发能的提高；共混物断裂韧性提高的原因是由于外加应力场在ＰＰＳ微纤附近产生应力集中，促使基体和微纤都发生塑性形变，从而吸收更多的能量所致。     

PP—g —HMA增容尼龙6／聚丙烯共混物结构与性能研究

采用固相力化学方法制备的聚丙烯接枝羟甲基丙烯酰胺作增容剂,制备了尼龙6／聚丙烯共混物,通过SEM、DSC、流变性能测试和力学性能测试研究了共混物的结构、流变性能和力学性能。 结果表明,当尼龙6体积分数为80％时,增容共混体系中冲击强度出现峰值,达到77J／m,分散相尺寸变小,增容共混体系熔融粘度增加。通过Molau实验和FT－IR分析对增容机理作了初步探讨。     

汽车用高流动性共聚聚丙烯的工业生产

在气相法聚丙烯生产装置上成功地开发出汽车用共聚聚丙烯系列树脂,研究了该树脂的力学性能及热性能。结果表明,它们具有高冲击强度、适宜的弯曲模量及硬度,Izod冲击强度常温为7～12k/m^2．低温为3-4kJ／m^2,弯曲模量为900-1200MPa,洛氏硬度大于85。     

聚丙烯高性能化改性研究

研究了橡胶和弹性体的种类与用量、加工助剂等对聚丙烯(PP)的悬臂梁缺口冲击强度、拉伸强度、硬度、加工性能以及透明性的影响。结果表明:与添加其他橡胶的PP相比,添加乙丙橡胶(EPR)1的PP合金具有较高的悬臂梁缺口冲击强度、透光率及流动性,较低拉伸强度与硬度;添加聚乙烯蜡的PP的综合性能最好。     

Mechanical and thermal properties of polycarbonate. II. Influence of titanium dioxide content and quenching on pigmented polycarbonate

The effects of quenching temperature including different thermal histories on mechanical, physical, and thermal properties of pigmented polycarbonate (PC/TiO₂) were investigated. Tensile test, Izod impact strength and heat distortion temperature (HDT) were performed on specimens of 3 mm thickness. Pigment content and quenching temperature are two key factors that affect the properties of the materials. A higher content of pigments results in an increase of modulus of elasticity and a decrease of unotched and notched Izod impact strength, as well as elongation at break. A maximum of yield stress and HDT is obtained at 3% of TiO₂, which was considered as the optimum level of pigment. An additional second quenching at 40°C has allowed to improve Izod impact strength and elongation at break of specimens with 3% of TiO₂; whereas modulus of elasticity, density, yield stress, and HDT were minimum at this quenching temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fracture and impact strength of poly(vinyl chloride)/methyl methacrylate/butadiene/styrene polymer blends

The Izod impact strength of poly(vinyl chloride)/methyl methacrylate/butadiene/styrene(PVC/MBS)polymer blends can be changed significantly with different levels of MBS and/or MBS particle size. The following results were obtained by investigating the fracture of PVC/MBS test specimens: (1) The dependence of the Izod impact strength of PVC/MBS blend on MBS particle size confirms a maximum around a MBS particle size of 2000 Å. When MBS particle size is smaller than 2000 Å, the Izod impact strength increases with MBS particle size, and crazing occurs mainly in this region. When MBS particle size is larger than 2000 Å, then the Izod impact strength, in contrast, decreases with increasing MBS particle size, and both crazing and shear yielding occur, mainly in this region. (2) Tensile experiments of PVC/MBS blends carried out under various conditions showed that the amount of energy absorption increases with decreasing MBS inter-particle distance and with increasing MBS particle size when crazing is the main energy absorbing mode. The MBS inter-particle distance dominates the energy absorption when shear yielding is the main energy absorbing mode. (3) Therefore, the Izod impact strength of PVC/MBS blends and the maximum around a MBS particle size of 2000 Å can be explained as follows: Below 2000 Å, the energy absorption by crazing dominates the total energy absorption, and the energy absorption by crazing increases with MBS particle size. Above 2000 Å, the energy absorption by shear yielding is dominant, and the energy absorption by shear yielding increases with decreasing inter-particle distance, that is to say, decreasing MBS particle size.     

新型增韧剂在尼龙6上的应用

比较了增韧剂I-NY与橡胶类、聚烯烃类增韧剂对尼龙6性能的影响。结果表明，随着增韧剂I-NY用量的增加，尼龙6的缺口冲击强度显著提高，当其质量分数为15％时，缺口冲击强度为28kJ／m^2，是纯尼龙6的10倍；且在改善冲击强度的同时，材料的弯曲和拉伸强度下降较少，是一种比较理想的尼龙增韧剂。     

Impact strength of polymers 2: The effect of cold working and residual stress in polycarbonates

The influence of cold working on the toughness improvement in glassy amorphous polycarbonates was studied. Cold working processes, namely rolling and. Steckel rolling were used to produce thickness reductions up to 40 percent in flat-strip specimens. The notched Izod impact strength and tensile properties were measured as a function of strip thickness reduction. It was shown that the toughness enhancement in polycarbonates cold worked to low thickness reductions was due to the residual stress state present as opposed to molecular orientation which becomes significant at higher degrees of cold work. Residual stress measurements were made by using the layer removal technique. Residual tensile stresses as high as 2100 psi were present in 1/4-in. cold-rolled polycarbonate at the surface. The maximum stress in the center of the specimen was 1100 psi in compression. The residual stresses at the surface decreased with increasing thickness reduction. The residual stress state for Steckel rolled. 1/2-in. polycarbonate was also measured and found to be more complex than for the thinner samples, The results demonstrated that surface tensile stresses and interior compressive stresses can produce large values of impact strength if the notch is to be machined after cold working. Thus, the values of impact strength measured from the notch Izod specimen are sensitive to the residual stress state in the polymer. This behavior is in contrast to earlier studies on thermally quenched material in which the material was quenched after notching. The thermal quenching produced surface compressive stresses which were also present at the notch tip. The presence of compressive residual stresses at the center of the notch suppressed the formation of a craze leading to toughness enhancement in cold worked polycarbonate strips. It is shown that by control of residual stresses in polycarbonate, strips at least 1/2 in. in thickness can be made to exhibit ductile failure in the notched Izod impact test.