发泡剂对EPDM海绵性能的影响

采用模压一步法制备EPDM海绵。研究发泡剂品种和用量对其性能的影响。结果表明，以发泡剂AC，OBSH或H制备EPDM海绵，最佳用量分别为5，5和3份；发泡剂用量为5份时，以发泡剂H制备的EPDM海绵发泡倍率最大。以发泡剂AC／OBSH，AC／H或OBSH／H并用制备EPDM海绵，最佳并用量分别为5，4和2份；发泡剂并用量为5份时，以发泡剂AC／OBSH并用制备的EPDM海绵发泡倍率最大。扫描电子显微镜观察发现．以发泡剂AC／OBSH井用制备的EPDM海绵微孔分散均匀。     

发泡剂对EPDM发泡橡胶性能的影响

采用热空气自由发泡制备EPDM发泡橡胶,研究发泡剂品种和用量对其性能的影响。结果表明,以发泡剂OBSH、AC和H制备EPDM发泡橡胶时,它们的最佳用量分别为10份、15份和10份;当发泡剂用量为10份时,以发泡剂OBSH制备的EPDM发泡橡胶发泡倍率最大。观察发泡橡胶内部结构发现,用发泡剂OBSH制备的EPDM的发泡橡胶内部泡孔结构较均匀、孔径最小。     

促进剂对三元乙丙橡胶海绵性能的影响

研究促进剂品种和用量对三元乙丙橡胶(EPDM)海绵性能的影响。结果表明:在一定的发泡体系下,硫化速率对EPDM海绵的结构和性能影响很大;采用发泡剂AC/OBSH/尿素并用体系,当硫化体系及用量为硫黄1.2,促进剂TMTD 1,促进剂M 0.8,促进剂PZ 1.2,促进剂BZ 1.5时,所得EPDM海绵呈微孔结构,泡孔分布均匀,综合性能良好。     

发泡剂对丙烯酸酯橡胶发泡材料性能的影响

采用模压法制备丙烯酸酯橡胶(ACM)发泡材料,研究了发泡剂品种和用量对其性能的影响。结果表明:以发泡剂4,4'-氧代双苯磺酰肼(OBSH)或偶氮二甲酰胺(AC)制备ACM发泡材料时,最佳用量分别为ACM用量的6%和7%;以复合发泡剂AC/OBSH、AC/碳酸氢钠、OBSH/碳酸氢钠分别制备ACM发泡材料时,最佳使用量分别为ACM用量的7%、7%、6%;当三组复合发泡剂使用量相同时,复合发泡剂AC/OBSH制备的ACM发泡材料发泡倍率最大,微孔孔径较一致,分散均匀。     

EPDM海绵密封条硫化体系与发泡体系的匹配研究

为研究EPDM硫化体系与发泡体系的匹配问题,采用不同硫化促进剂和不同有机发泡剂安排了4因素3水平的正交试验。结果表明,采用硫化活性较高的促进剂组合,所得胶料焦烧时间较短,交联程度较高,海绵密封条表面相对较为光滑,但发泡倍率不足;采用较慢硫化促进剂组合,所得海绵密封条外观质量最差,表面不光滑。发泡剂AC的分解温度高于发泡剂OBSH,应与稍慢硫化体系配合;发泡剂OBSH容易发泡,应与较快硫化体系配合,所得海绵密封条的表面质量较好。     

低冲击回弹性三元乙丙橡胶开孔海绵的制备

研究了三元乙丙橡胶开孔海绵的制备方法。结果表明,此EPDM开孔海绵能够在EPDM发泡过程中而不是在发泡后转变为开孔,因而材料的冲击回弹性降低,填充性能提高。将0.1~40份有机发泡剂、2~40份无机发泡剂、2~40份辅助剂进行混合、硫化和发泡,所得EPDM开孔海绵具有较低的冲击回弹性和优良的密封性能,可用作各种工业制品的密封材料。     

可膨胀微球发泡剂制备EPDM海绵的研究

采用可膨胀微球发泡剂MSH-500通过模压硫化法制备EPDM海绵,研究硫化剂DCP用量、发泡剂MSH-500用量和硫化温度对EPDM海绵性能的影响.结果表明:硫化剂DCP用量为3份、发泡剂用量为5份、在140℃下硫化15 min制备的EPDM海绵综合性能较好,且海绵泡孔分布均匀,孔径均一.     

EPDM预成型模压发泡材料的研制

本文采用快压型炭黑N550作为橡胶补强填料,研究了加工工艺、发泡剂添加量、硫化体系对EPDM发泡材料的影响。研究表明:①采用三段塑炼工艺进行EPDM预成型模压发泡,物料混炼更均匀;②当发泡剂用量高于2份时,制备出的EPDM发泡材料是开、闭孔混合结构的发泡材料;③当硫化体系用量增加8%时,有较好的交联程度,力学性能较好,硫化过程与发泡过程匹配较好,橡胶海绵具有较好的微孔结构。     

高速铁路板式无碴轨道海绵胶垫的研制

介绍高速铁路板式无碴轨道海绵胶垫的研制。采用主体材料为EPDM、朴强填充体系为高耐者炭黑／陶土并用体系、硫化体系为硫化剂DCP／硫黄／促进剂并用体系、发泡体系为发泡剂OBSH／三乙醇胺并用体系的配合制备的高速铁路板式无碴轨道海绵胶垫性能达到指标要求，在遂渝铁路试验段试铺效果较好。     

发泡剂和废旧胶粉用量对EPDM发泡性能的影响

采用模压化学发泡法制备了EPDM/胶粉共混发泡材料。利用均匀实验设计法设计了实验,研究了废旧胶粉和化学发泡剂用量对EPDM发泡材料硫化特性、力学性能的影响,并通过神经网络和遗传算法对实验数据进行处理。结果表明,随着胶粉用量的增加,发泡材料的交联作用和发泡进程均有所减弱,当胶粉用量在20份以下,发泡剂用量在9~12份时,发泡材料的综合性能较好。     

氯化聚乙烯/三元乙丙橡胶共混发泡材料性能的研究

以氯化聚乙烯/三元乙丙橡胶(CM/EPDM)并用胶为基材制得发泡材料,研究了DCP用量和发泡体系对发泡材料性能的影响。结果表明,在DCP用量为2份、AC用量为8～12份时,硫化速率和AC分解发泡速率匹配较好,发泡材料泡孔细密均匀,表面光滑,制品综合性能最佳;在所研究的3种发泡助剂(硬脂酸锌,ZnO和纳米ZnO)中,含ZnO和纳米ZnO的发泡材料外观较好、性能优良;当ZnO用量为6～8份时,发泡制品密度较低,性能较好。     

Mechanical and morphological properties of cellular NR/SBR vulcanizates under thermal and weathering ageing

The effects of addition of two chemical blowing agents in cellular rubber blend of natural rubber (NR) and styrene‐butadiene rubber (SBR) at a fixed blend ratio of 1 : 1 on cure characteristics, and mechanical and morphological properties were invesigated. The chemical blowing agents used in this work were Oxybis (benzene sulfonyl) hydrazide (OBSH) and Azo dicarbonamide (ADC). Three different fillers, fly ash (FA) particles, precipitated silica, carbon black (CB) at their optimum concentrations of 40 phr were used, the FA and silica particles being chemically treated by bis‐(3‐triethoxysilylpropyl) tetrasulphide. The results suggested that the overall cure time decreased with OBSH and ADC contents. The OBSH was more effective in cure‐acceleration of the NR/SBR blend than the ADC. The NR/SBR vulcanized foams produced by OBSH and ADC agents had closed‐cell structures. The specific density and mechanical properties of the blend tended to decrease with increasing blowing agent content. The CB gave NR/SBR foams with smaller cell size, better cell dispersion, and higher mechanical properties than the precipitated silica and FA particles. The heat ageing and weathering resulted in an increase in tensile modulus and hardness, but lowered the tensile strength, ultimate elongation and tear strength. The elastic recovery for cellular NR/SBR vulcanizates with FA was superior to that with CB and silica, the elastic recovery of the blends decreasing with blowing agent content. Resilience property was improved by the presence of gas phases. The optimum concentration of OBSH and ADC to be used for NR/SBR vulcanizates was 4 phr. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

不同发泡剂及工艺条件对BR／SBR／NR发泡材料相结构及尺寸稳定性的影响

分别采用一段和两段模压法制备了以顺丁橡胶（BR）／丁苯橡胶（SBR）／天然橡胶（NR）为基体的橡胶发泡材料,研究了三种化学发泡剂N,N＇-二甲基戊次甲基四胺（H）、4,4＇-氧代双（苯磺酰肼）（OBSH）以及H／OBSH（质量比1：1）复配对发泡及硫化特性的影-向,以及3种发泡剂和2种成型工艺对收缩率及相结构的影响。结果表明,发泡剂H对硫化性能影响最大,含发泡剂H的混炼胶在分解过程中释放的热量最多;加入3种发泡剂都具有一种较大的泡孔镶嵌在较小的泡孔丛中的泡孔形态;密度和线收缩率均随着时间的增加而增加,经H／OBSH复配的发泡剂更适合该体系成型,材料线收缩率均比单独使用H和OBSH小,两段模压法可以有效地提高发泡材料的尺寸稳定性,收缩率降低至3．88％,同时发泡剂使用率最多可提高31．67％。     

挤出发泡MVQ海绵的结构与性能

采用挤出发泡方法制备甲基乙烯基硅橡胶(MVQ)海绵,研究白炭黑、硫化剂和发泡剂用量对MVQ海绵泡孔结构和性能的影响.结果表明:MVQ海绵中含有大量闭孔结构,不同密度海绵的泡孔尺寸及分布密度存在差异;采用较低用量的白炭黑和发泡剂、较高用量的硫化剂可以得到密度和硬度较大的MVQ海绵;MVQ海绵的压缩应力松弛率随着密度的增大呈现先增大后减小的趋势,在密度为0.61 Mg·m-3时达到极大值18％;在低应力区域内,密度较大的试样应力增幅比密度较小的试样大.     

Rheological properties and foam processibility of precured EPDM

EPDM foam was prepared by dynamically vulcanizing EPDM compound in a HAAKE rheometer firstly, then mixing the partially precured EPDM compound with a blowing agent and a sulfur vulcanizing system on a two roll mill. The compound was extruded through a cold feed extruder, and the extrudate was foamed in a circulating hot air oven. EPDM compound was vulcanized partly in the HAAKE rheometer, the final torque increases with increasing sulfur content. Rheological measurement shows the dynamic storage modulus, the loss modulus, and the complex viscosity of precured EPDM compound increase with increasing sulfur content. Then the partially precured EPDM compound was compounded with a blowing agent and a sulfur vulcanizing systems, Rheometric measurement shows that the rate of vulcanization of partially precured EPDM compound is not affected by the precure. The blowing results show that the foam processibility could be improved and the expansion ratio increases in the same processing condition for optimum partially precured EPDM compound, which indicates the optimum crosslink density for EPDM could enhance the efficiency of blowing agent AC. SEM shows that the foam articles have a closed‐cell structure with few open cells, and the large cells inlay among the small cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3387–3394, 2006     

发泡剂AC的热分解活化机理及影响因素*

采用动力学和热力学相结合的方法,用自行设计的发泡剂发气量测量装置研究了重金属盐、金属氧化物、有机酸及其盐等对发泡剂ＡＣ热分解特性的影响;用ＤＳＣ差示扫描量热仪测定了各体系的动态分解温度和热效应。结果表明,三盐基硫酸铅、二盐基亚磷酸铅、硬脂酸铅和柠檬酸对发泡剂ＡＣ都有较强的活化作用,属于加速型发泡助剂;氧化锌是发泡剂ＡＣ较理想的活化引发剂,当其用量为０１份时,活化作用较好;而硬脂酸、硬脂酸钡和柠檬酸钠的活化作用较小,属于延缓型发泡助剂     

动态硫化三元乙丙橡胶(EPDM)/聚丙烯(PP)热塑性弹性体的力学性能

研究了双螺杆挤出机制备EPDM/PP热塑性弹性体的工艺条件对其力学性能的影响,结果显示,当橡塑比为60/40.EPDM与PP预混合两次,双螺杆挤出机转速约9.5Hz,硫化剂的量为10份时,热塑性弹性体有较好的力学性能。     

Study on foaming kinetics and preparation of EPDM foams

Abstract

The ethylene–propylene–diene terpolymer (EPDM) foam article was prepared by mixing a compound in a two roll mill, extruding the compound through a cold feed extruder and finally vulcanising the extrudate in a circulating hot air oven. The blowing kinetics of EPDM compounds was studied using a moving die rheometer, and the effect of blowing agent content and process temperature on the cell structures was investigated. The results show that kinetic parameters determined from the autocatalystic model equation have good agreement with the experimental results. The calculated activation energy of azodicarbonamide (AC) decomposition is higher than that of rubber cure, which indicates the rate of blowing agent AC decomposition accelerates more quickly than that of rubber vulcanisation with increasing temperature. The density of foam article decreases with increasing blowing agent content or elevated temperature. The foams have a closed cell structure and the larger cells inlay among the smaller cells, which shows cell materials with structural multihierarchy. This shows the rubber vulcanisation and blowing agent decomposition could match only using extremely slow accelerator diphenylguanidine (DPG), which is dissimilar to the conventional EPDM sponge requiring very quick scorch.