酸凝固天然橡胶和微生物凝固天然橡胶硫化特性研究

采用硫化仪分析2种天然橡胶的硫化过程,探讨了炭黑和硫化温度对硫化诱导期、正硫化时间和最大转矩的影响。研究结果发现：微生物凝固胶和酸凝固胶的硫化诱导期和正硫化时间随硫化温度的上升显著下降,且都能很好符合阿仑尼乌斯方程;胶样的最大转矩与硫化温度呈很好的线性关系,且随着硫化温度的升高,逐渐降低;当采用纯胶配方时,微生物凝固胶的MH0显著高于酸凝固胶,而加入炭黑后．2种胶样的MH0均显著提高。但微生物凝固胶的MH0稍低于酸凝固胶。     

恒粘剂硫酸联胺对天然橡胶硫化特性的影响

研究恒粘剂硫酸联胺对天然橡胶(NR)硫化特性的影响。结果表明:在NR中加入恒粘剂硫酸联胺,胶料的t_(10)缩短,t_(90)延长;随着硫化温度的升高,NR和恒粘天然橡胶(CVNR)胶料的t_(10)和t_(90)缩短,NR胶料的t_(10)对温度的依赖性小于CVNR胶料,t_(90)对温度的依赖性大于CVNR胶料;NR胶料的t_(10)对t_(90)的影响灵敏度大于CVNR胶料;NR和CVNR胶料的M_H随硫化温度的升高而减小。     

增粘剂对天然橡胶硫化特性及力学性能的影响

研究了增粘剂盐酸联胺和硫酸联胺对天然橡胶（NR）硫化特性及在热氧（热空气）、臭氧、光氧（紫外光）老化前后力学性能的影响。结果表明,随着盐酸联胺和硫酸联胺用量的增加,最大转矩（MH）和转矩差Δ（MH-ML）降低,焦烧时间（ts2）和正硫化时间（t90）延长,硫化速率（Vc）降低;热氧、臭氧、光氧老化前后定伸应力有所降低,热氧老化前的拉伸强度降低,老化后的拉伸强度增加,臭氧和光氧老化后的拉伸强度降低,拉断伸长率上升。     

配合剂对白色天然橡胶硫化胶变色和变黄的影响

主要讨论各种配合剂对白色天然橡胶（NR）硫化胶变色和经紫外线照射后变黄的影响。结果表明,在白色NR硫化胶配合体系中,钛白粉为最好的白色着色剂 硫化体系可选普通硫黄硫化体系或DTDM有效硫黄硫化体系 普通硫黄硫化体系中促进剂以TMTD,ZDC,TRA,TMTM,PZ,BZ为好 防老剂可选用MB,1010,264,SPC 填料可选用轻质碳酸钙、硫酸钡和白炭黑,如选用白炭黑,其对应的活化剂以丙三醇为好 软化剂可选用白油、石蜡油、凡士林、机油 紫外线吸收剂用量在0.5质量份以上。这样配制的白色NR硫化胶的白度较高,在紫外线照射下胶料变黄程度也较小。     

环氧化天然橡胶的硫化特性

用过醋酸法制得的系列环氧化天然橡胶(简称ENR。用硫化仪研究其硫化特性,焦烧性能,助剂影响。通过硫化主硫化期(稳态期)测定ENR有促进剂的硫黄硫化反应动力学级数,表观反应速度常数及表观活化能。     

硫化体系对天然橡胶性能的影响

研究普通硫化体系和半有效硫化体系对天然橡胶(NR)各项性能的影响。结果表明:与普通硫化体系NR胶料相比,半有效硫化体系NR胶料的硫化返原程度小,物理性能、压缩疲劳性能、耐磨性能和耐热老化性能好,且随着促进剂用量的增大性能更优,但耐切割性能变差;随着硫化时间的延长,普通硫化体系和半有效硫化体系NR胶料的压缩疲劳温升和磨耗量均增大,且普通硫化体系胶料增幅更大。     

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Abstract

The cure time of accelerated sulphur vulcanization of Epoxidized Natural Rubber (ENR 25) was studied while one grade of unmodified natural rubber– Standard Malaysian Rubber Light (SMR L) was used as a control. Five accelerators, viz. 2-mercaptoben-zothiazole (MBT), tetramethylthiuram disulphide (TMTD), zinc dimethyldithiocarbamate (ZDMC), N-tert-butyl-2-benzothiazylsulphenamide (TBBS) and diphenylguanidine (DPG) were used in the study and the vulcanization systems used were conventional vulcanization (CV), semi-efficient vulcanization (semi-EV) and efficient vulcanization (EV). Monsanto Moving-Die Rheometer (MDR 2000) was used to determined the cure time in the temperature range of 100-180°C. The results indicate that cure time decreases exponentially with increasing temperature for the two rubbers studied. At a fixed curing temperature, ENR 25 shows shorter cure time compared to that of SMR L. This has been attributed to the activation of the double bond by the adjacent epoxide group in ENR 25. Studies of the effect of varying amounts of M Bata a fixed sulphur concentration show that cure time decreases as the accelerator concentration increases. ENR 25 shows higher torque maximum than SMR L. This observation can be related to the oxirane group which is bulky and thus accounts for increased glass; transition temperature with increase in the level of epoxidation. Of the vulcanization systems, CV shows the highest torque maximum followed by semi-EV and than EV. This trend can be attributed to the amount of active sulphurating agent which increases with increasing accelerator concentration. It was also found that the influence of accelerator/sulphur ratio becomes less significant as vulcanization temperature increases.     

硬脂酸钙对ENR25硫化动力学的影响

采用流变仪测定添加不同硬脂酸钙用量的环氧化程度为25的环氧化天然橡胶(ENR25)的硫化曲线,研究硬脂酸钙用量对环氧化天然橡胶硫化动力学参数的影响。研究结果表明,随着硬脂酸钙用量的增加,反应速率常数k增大,硫化反应活化能E降低,表明硬脂酸钙的加入有助于促进ENR25的硫化,这可以减少生产过程中能耗,提高生产效率。     

硅烷偶联剂KH550对炭黑填充天然橡胶性能的影响

研究不同用量的硅烷偶联剂KH550对炭黑填充天然橡胶的硫化特性、物理性能和动态力学性能的影响。结果表明,硅烷偶联剂KH550的加入缩短了焦烧时间和正硫化时间;硅烷偶联剂KH550添加量为2份时邵尔A型硬度和拉伸强度达到最大值,拉断伸长率有所降低,回弹性和压缩永久变形性能有明显改善;硅烷偶联剂KH550的加入能有效降低炭黑的Payne效应,提高胶料的交联密度及炭黑的分散性,硫化胶损耗因子和动态生热降低,动态力学性能明显改善。     

The Effect of Ethylene Diamine Dilaurate and Silane Coupling Agent on Cure Characteristics,Mechanical, and Thermal Properties of Silica-Filled Natural Rubber Composites

The influence of a new coupling agent, ethylene diamine dilaurate (EDD) and a commercial silane coupling agent, (Si-69) on the cure characteristics, mechanical and morphological properties of silica-filled natural rubber (NR) composites was studied. The results show that scorch time and cure time decreased with an increase in both coupling agents' content, but maximum and minimum torques exhibit the opposite trend. The mechanical properties such as tensile strength and tensile modulus, M100 and M300, increased with increasing both coupling agents' content but at a similar coupling agent content, silica-filled natural rubber composites with Si-69 exhibit better tensile strength (more than 2 phr) and tensile modulus than does EDD. Elongation at break (Eb) of silica-filled natural rubber increased with increasing EDD content but Si-69 exhibits the opposite trend. Scanning electron microscopy (SEM) study of tensile fracture surfaces shows the better tensile strength of silica-filled natural rubber composites with Si-69 and EDD over control composites (without EDD or Si-69). Thermogravimetric analysis (TGA) results indicate that silica-filled NR composites with EDD have higher thermal stability than Si-69. Fourier transform infrared spectra (FTIR) provided an evidence of interaction between EDD and Si-69 with silica in NR composites.     

橡胶固化的流变学研究

本文的目的是得到一种快速、可重复的方法来反映并量化两种不同橡胶产品在固化温度下结构的形成,从控制应力屈服测试和蠕变测试结果我们发现流变学方法可以用来很好的表征橡胶的固化。     

Curing Characteristics and Aging Properties of Natural Rubber/Epoxidized Natural Rubber and Cellulose II

In this work, natural rubber (NR) and regenerated cellulose (cel II) latexes were co-coagulated and to the mixture epoxidized natural rubber (ENR) was added on a two-roll mill. The cellulose content was fixed at 20 phr while ENR content varied from 0 to 75 phr. The influence of ENR was studied through the cure characteristics, aging and dynamic-mechanical properties. The aging provides nanocomposites with better solvent resistance and increased tensile strength at ENR content of 25 phr. The results suggest that a new type of light-colored nanocomposites were obtained, which presented high mechanical performance and resistance to solvents.     

补强剂对三氯溴甲烷改性天然胶乳力学性能的研究

对用纳米SiO2和纳米CaCO3补强三氯溴甲烷改性天然胶乳的性能进行了研究。结果表明．纳米SiO2和纳米CaCO3对三氯溴甲烷改性天然胶乳具有一定的补强作用．随补强剂用量的增加．胶膜力学性能呈上升趋势,但当补强剂用量达到一定程度时,随补强荆用量增加补强效果变差。     

天然橡胶/有机蒙脱土纳米复合材料的硫化特性

采用机械混炼法制备了天然橡胶/有机蒙脱土(NR/OMMT)纳米复合材料,对其硫化特性进行了研究。红外光谱(FTIR)表明,有机改性剂(OM)已经插层进入蒙脱土(MMT)片层,热重分析(TGA)测得OM-MT中OM质量分数为0.364;差示扫描量热(DSC)和硫化特性表明,MMT对NR的焦烧时间(Ts)和正硫化时间(T90)没有影响,但降低了NR的交联密度;NR的Ts随OMMT含量的增加逐渐降低,而T90变化不大,NR的交联密度随OMMT含量的增加先增大后减小;温度升高,复合材料的硫化效率提高,交联密度降低。