动态硫化NBR/HPVC热塑性弹性体的性能研究

研究了动态硫化NBR／高聚合度聚氯乙烯（HPVC）热塑性弹性体的硫化特性、物理性能及加工性能。试验结果表明，PVC聚合度越大，NBR／HPVC共混比越大，动态硫化NBR／HPVC的加工性能越差；当橡塑共混比为70／30，动态硫化温度在150－155℃时，采用硫化剂TMTD硫化体系制备的动态硫化NBR／HPVC的综合物理性能优良，热塑性较好，可重复加工。     

NBR/PVC热塑性弹性体的性能研究及应用

选用不同硫化体系,用动态硫化法制备了丁腈橡胶(NBR)/聚氯乙烯(PVC)热塑性弹性体,考察了硫化体系、增塑剂邻苯二甲酸二辛酯(DOP)用量、填料种类、NBR与PVC的质量比对热塑性弹性体性能的影响.结果表明,采用过氧化二异丙苯/硫磺复合硫化体系硫化的热塑性弹性体的性能较好;炭黑的增强效果优于白炭黑和轻质碳酸钙;DOP用量增加,热塑性弹性体的综合力学性能下降;NBR与PVC的质量比增加,热塑性弹性体的柔性增加.所研制的NBR/PVC经压延塑化造粒、注射成型可以制得某品牌汽车的油箱密封垫片,极大地提高了生产效率,提高了市场竞争力.     

动态硫化NBR/PFPA热塑性弹性体热性能的研究

试验研究动态硫化NBR／石油发酵尼龙（PFPA）热塑性弹性体的热性能。结果表明，随着PFPA用量的增大，动态硫化NBR／PFPA热塑性弹性体的玻璃化温度升高，熔点降低，熔融焓减小，热稳定性提高；动态硫化NBR／PFPA热塑性弹性体的热降解过程分2个阶段进行，且2个阶段均为一级反应。     

开炼机与密炼机动态硫化制备NBR／PVC热塑性弹性体的研究

对比并讨论了采用开炼机动态硫化与采用密炼机动态硫化制备的NBR／PVC热塑性弹性体的物理机械性能、流变性能、形态结构,通过对试验结果的分析,认为动态硫化应以采用高剪切、高温密炼机为宜。     

PVC/NBR热塑性弹性体热塑性能的研究

将动态硫化方式制备的PVC/NBR老化前后制品力学性能与重复加工后PVC/NBR制品老化前后力学性能进行对比，发现所制备的PVC/NBR共混体具有热塑性，同时对PVC/NBR热塑性弹性体有了比较深刻的了解。     

NBR/三元尼龙/二元尼龙三元共混型热塑性弹性体制备工艺与性能的研究

在开炼机上用动态硫化法制备了NBR／三元尼龙／二元尼龙三元共混型热塑性弹性体。研究了共混工艺、返炼次数、动态硫化温度、二元尼龙用量等因素对材料性能的影响。NBR／三元尼龙／二元尼龙三元共混型热塑性弹性体不仅具有优异的耐溶剂性，而且其物理性能也较好。     

NBR/PVC热塑性弹性体耐热老化性能研究

考察了硫化体系、PVC聚合度、DOP用量、抗氧剂种类及用量对丁腈橡胶／聚氯乙烯(NBR／PVC)热塑性弹性体(TPE)的耐热老化性能的影响。试验结果表明：NBR／PVC：的质量比为70：30时，酚醛树脂硫化体系制备的TPE的耐热老化性能最好；增加PV(：的聚合度，TPE的耐热老化性能提高；DOP用量越大。TPE的耐热老化性能越差；抗氧剂2246对TPE的耐热老化性能最好，其最佳用量为2．0份。     

三元共聚尼龙/聚氯乙烯/丁腈橡胶三元共混弹性体研究

选择三元共聚尼龙（PA），聚氯乙烯（PVC）和丁腈橡胶（NBR）为主体材料，采用高温机械共混，化学交联工艺制得了PA／PVC／NBR三元共混弹性体，探讨了PA／NBR，POM／NBR，PVC／NBR，HMWPVC／NBR三元共混体系性能，重点讨论了PA／PVC／NBR共混比，不同硫化体系，有机过氧物DCP用量等因素对PA／PVC／NBR三元共混弹性体性能的影响，实验结果表明：选择适宜配方制得力学性能和耐油耐溶剂性能较好的PA／PVC／NBR三元共混弹性体，扫描电镜的实验结果证实m(PA):m(PVC):m(NBR)=10:30:60和m(PA):m(PVC):m(NBR)=30:10:60两个体系的三元共混弹性体均具有较好的相容性，且前者的相容性更好。     

动态硫化NBR/CPE/EVA热塑性弹性体的研制

为了获得一种耐热油，弹性好，强度高，橡胶感强，易加工的油封材料，我们采用动态硫化法制备了共混型NBR／CPE／EVA热塑性弹性体，系统讨论了橡塑并用比，硫化温度和硫化时间对热塑性弹性体的凝胶含量及力学性能的影响。结果表明：在一定温度和时间范围内，硫化温度升高和硫化时间延长，热塑性弹性体的凝胶含量增大，随着热塑性弹性体中EVA用量增大，弹性体的拉伸强度，赵氏硬度和拉伸永久变形有增大。     

NBR/HPVC热塑性弹性体的性能研究Ⅱ

选用丁腈橡胶(NBR)和高聚合度聚氯乙烯(HPVC)为主体材料,用动态硫化法制备了一类性能优异的材料—丁腈橡胶/高聚合度聚氯乙烯共混型热塑性弹性体(TPE),研究了共混方法,硫化温度,硫化体系,硫化剂用量,硫化时间等因素对动态硫化NBR/HPVC热塑性弹性体力学性能的影响。     

Fatigue Behavior of Dynamically Vulcanized Poly(Vinyl Chloride)/Nitrile Butadiene Rubber Thermoplastic Elastomers

Abstract

Dynamically vulcanized poly(vinyl chloride)/nitrile butadiene rubber (PVC/NBR), thermoplastic elastomers (TPEs) were melt mixed at 150°C and 50 rev. min.^?1 with a Brabender Plasticorder. Curatives concentration was varied from 0 to 1 phr in order to study the effect of dynamic curing on the plastified formulations. The compounds were characterized with respect to their fatigue life, the strain energy and its exponent, rebound resilience, abrasion resistance, and viscoelastic behavior. Profound enhancement in the fatigue life of the dynamically vulcanized formulations reduced damping and improved rebound resilience. The observed scenario has been attributed to the increase in the degree of curing.     

Rheological and mechanical properties of dynamically cured poly(vinyl chloride)/nitrile butadiene rubber thermoplastic elastomers

Plasticized poly(vinyl chloride)/nitrile butadiene rubber (PVC/NBR) thermoplastic elastomers (TPEs) were dynamically cured in the melt stage with the incorporation of a semi‐efficient curing system using a Brabender Plasticorder at 150 °C and rotor speed of 50 rev min^?1. Sulfur concentration was progressively increased from zero to 1 part per hundred NBR to study the effect of dynamic curing on mechanical and rheological behaviour of the TPEs. The compounds were characterized in respect of their rheological and mechanical properties. The effectiveness of dynamic curing was studied using Brabender plastograms, a moving disc rheometer and swelling index measurement. The mechanical properties investigated include tensile strength, elongation at break, modulus at 100% elongation, tear strength and hardness. The influence of thermooxidative ageing on the mechanical properties was investigated by incubating the PVC/NBR TPEs in an air oven at 80 °C for 168 h. The torque values obtained from both rheometers increased with increasing sulfur dosage, while the swelling index decreased. The significant increase in the degree of curing evidenced by the steady reduction in the swelling index provided excellent proof of the efficiency of the dynamic curing technique. Thermo‐oxidative ageing resulted in a pronounced enhancement in mechanical properties as a function of sulfur content. This observation seems to indicate that some microstructural changes, such as the formation of new crosslinks, occur in the thermo‐oxidatively aged TPEs. This trend was supported by further reduction in the swelling index of the aged TPEs. © 2003 Society of Chemical Industry     

氯化聚乙烯对三元乙丙橡胶与丁腈橡胶并用胶物理机械性能的影响

研究了氯化聚乙烯对EPDM／NBR并用胶物理机械性能的影响。结果发现，加入氯化聚乙烯后，并用胶的混合平衡扭矩降低，达到平衡扭矩所需的时间缩短，且无论用硫黄硫化还是用过氧化物硫化，硫化胶的物理机械性能都提高，表明氯化聚乙烯对EPDM／NBR并用胶有一定的增容作用。同时也发现用过氧化物硫化的EPDM／NBR并用胶物理机械性能优于硫黄硫化的并用胶物理机械性能。     

Rheological and Mechanical Properties of Clay-Thermoplastic Elastomers Derived from PVC and NBR

Based on the character of a clay that could be separated into many 1-nm thickness monolayers, clay poly(vinylchloride)-nitrile butadiene rubber (PVC/NBR) thermoplastic elastomers (TPEs) were acquired using a Brabender Plasticorder at 150°C and 50 rpm rotor speed. Clay concentrations were progressively increased up to 10 phr of PVC/NBR composites. The rheological behavior of the clay PVC/NBR blends was assessed by dynamic mechanical analysis, as well as Brabender torque rheometry. The results revealed that the complex modulus (E?) and elastic modulus (E′) increased with clay loading, indicating that the actual strength of the blends improved. Tensile properties of the PVC/NBR-clay formulations with different filling amounts were studied. The results showed that the mechanical performance of the rubbery samples improved with clay loadings. The observed trend has been attributed to the reinforcing role played by layered clay due to better dispersion as well as improved interactions.     

Oil Resistance of Dynamically Vulcanized Poly(Vinyl Chloride)/Nitrile Butadiene Rubber Thermoplastic Elastomers

Summary Dynamically cured poly(vinyl chloride)/nitrile butadiene rubber (PVC/NBR), thermoplastic elastomers (TPEs) were melt mixed at 150°C at 50 rev.min.^-1 with a Brabender Plasticorder. Curatives concentration was varied from 0 to 1 phr in order to study the effect of dynamic curing on the oil resistance of the plastified formulations. The compounds were characterized in respect to their mass swell, tensile properties, tear strength and hardness. The PVC/NBR formulations have been exposed to air and oil under otherwise identical conditions. The influence of oil and thermo-oxidative ageing on the mechanical properties were characterized at room temperature and 100°C. It was found that at ambient temperature the samples immersed in oil possessed similar properties to those that were exposed to air. Profound enhancement in mechanical properties were observed for both environments at 100°C. The observed scenario has been attributed to the increase in the degree of curing which was accompanied by a steady reduction in % mass swell with increased sulfur loading. The excellent mechanical behavior of the PVC/NBR TPEs even after immersing the samples in oil at 100°C evidenced for the good oil resistance of the materials.     

Effect of Mechanochemical Degradation on Rheological Behavior of PVC

The rheological behavior of mechanochemically degraded poly(vinyl chloride) (PVC) was studied through a Brabender plasticorder and capillary rheometer. The experimental results show that the degraded PVC has a much shorter plasticizing time, higher plasticizing rate, and lower melt viscosity and glass transition temperature as compared with undegraded PVC. The results provide a theoretical base for using the low molecular weight PVC prepared by the mechanochemical method as plasticizer for high molecular weight PVC.     

Effect of single-walled carbon nanotubes on morphology and mechanical properties of NBR/PVC blends

Dynamically vulcanized thermoplastic elastomer based on Nitrile butadiene-rubber (NBR)/PVC with functionalized single-walled carbon nanotubes (f-SWNTs) and non-functionalized single-walled carbon nanotubes (SWNTs) were prepared using a brabender internal mixer. Effects of two types of SWNTs (functionalized and non-functionalized) on morphology and mechanical properties of NBR/PVC blends were studied. Results showed that the mechanical properties of NBR/PVC/SWNTs nanocomposites improved with the increasing of SWNTs content and in particular with the increase of f-SWNTs content. Moreover, the enhancement of mechanical properties of NBR/PVC blends reinforced with functionalized SWNT was higher than that of NBR/PVC blends with non-functionalized SWNT. Dispersion of SWNTs and morphology of NBR/PVC/SWNT nanocomposites were determined by scanning electron microscopy and transmission electron microscopy (TEM) techniques. TEM images illustrated that f-SWNTs were dispersed uniformly in NBR/PVC matrix while non-functionalized SWNTs showed much aggregation. Dynamic mechanical thermal analysis of NBR/PVC/SWNTs nanocomposites was also studied. The outcomes indicated that in the case of f-SWNTs, the intensity of tan ?? peak was lower than that in the case of non-functionalized SWNTs. Meanwhile, the intensity of tan ?? peak reduced when the content of f-SWNTs was increased.     

Mechanical properties of PVC/SBR blends compatibilized by acrylonitrile-butadiene rubber and covulcanization

The mechanical properties of poly(vinyl chloride) (PVC)/styrene-butadiene rubber (SBR) blends compatibilized by acrylonitrile-butadiene rubber (NBR) were studied. A sulfur curing system was employed to crosslink the rubber of the blends. In the case of the blends without any curing agents, an increase in NBR content did not improve the tensile strength and elongation-at-break. However, a significant improvement in the mechanical properties was observed when NBR was added as a compatibilizer and the blend was vulcanized. In the PVC/NBR/SBR (50/10/40) blends, the tensile strength and elongation-at-break increased with an increase in sulfur concentration. This improvement was attributed to covulcanization between NBR and SBR. The fracture toughness of PVC/NBR/SBR (50/10/40) blends was characterized by the critical strain energy release rate, G_c. In the case of the PVC/NBR-29/SBR (50/10/40) blends, an increase in sulfur concentration resulted in a dramatic increase in G_c. However, the G_c value of PVC/NBR-40/SBR (50/10/40) blends decreased with an increase in sulfur concentration owing to the brittle behavior of one of the blend components—the PVC/NBR-40 (50/10) phase.     

氢氧化铝和炭黑对丁腈橡胶-聚氯乙烯复合材料硫化性能的影响

以氢氧化铝(ATH)为复合材料的添加型阻燃剂填充到丁腈橡胶-聚氯乙烯共聚物(NBR/PVC)体系中,采用不同比例的ATH和炭黑(CB)2种填充剂交替添加,制备出NBR/PVC复合材料;使用Haake流变仪对NBR/PVC复合材料基体的硫化参数和流变过程进行了研究,并与NBR/PVC纯树脂及含硅酮表面处理的ATH复合材料进行了对比试验。结果表明:使用硅酮对ATH的表面进行处理,虽然对NBR/PVC树脂材料不是非常有效,但能促进体系中无机填充剂和聚合物的空间点阵的交互作用;改变了ATH与树脂的比例,改善了它们的相互作用和加工性能,并通过流变过程得以验证。     

RAFT乳液聚合法合成线形三嵌段丙烯酸酯共聚物及其在PVC中的应用

摘要 本文采用可逆加成断裂链转移试剂（RAFT）通过乳液聚合法合成了分子量分布指数为1.8的甲基丙烯酸甲酯-g-丙烯酸丁酯-g-甲基丙烯酸甲酯（MMA-g-BA-g-MMA,MBM）三嵌段共聚物并将其与PVC进行共混。利用转矩流变仪测试了共混物的塑化行为;用动态力学谱仪(DMA)测试了共混物的动态力学行为并测试了共混物的力学性能。结果表明,MBM的加入可以有效减小PVC的塑化时间和平衡扭矩;随着MBM含量的升高,共混物储能模量 随MBM含量的增加出现一定程度的减小,力学内耗tanδ峰值先减小后增大,共混物的Tg升高了约5 ℃。当MBM含量在25 wt％时,共混物具有最大的冲击强度,相较于纯PVC提高了3.0倍。MBM可以作为PVC的一种有效的加工助剂和增韧助剂。