平衡硫化体系硫化天然橡胶的性能研究

对平衡硫化（ＥＣ）体系硫化天然橡胶（ＮＲ）的性能进行了研究，并与半有效硫化（ＳＥＶ）体系和传统硫化（ＣＶ）体系硫化ＮＲ进行了对比。结果表明，ＥＣ体系返原作用略高于ＳＥＶ体系，明显低于ＣＶ体系，硫化６ｈ时的返原率依次为７．７％，０．４％和３４．０％；与ＳＥＶ和ＣＶ体系相比，ＥＣ体系ＮＲ硫化胶拉伸强度、撕裂强度和３００％定伸应力高，生热低，耐磨性和耐屈挠性好。ＥＣ体系ＮＲ硫化胶的耐热氧老化性能优于ＳＥＶ体系，更优于ＣＶ体系。     

普通硫化体系和平衡硫化体系对不同硫化温度下 天然橡胶性能的影响

研究普通硫化体系（CV硫化体系） 和平衡硫化体系（EC硫化体系） 对不同硫化温度下天然橡胶（NR） 性能的影响。结果表明： 与采用CV硫化体系NR胶料相比, 采用EC硫化体系NR胶料在143和150 ℃ 下都具有较低的硫化返原率;经长时间硫化后的EC硫化体系NR硫化胶具有更低的损耗因子; 提高硫化温度, EC硫化体系NR硫化胶的物理性能降幅更小;143 ℃ 时EC硫化体系NR硫化胶经热空气老化后的物理性能保持率更高。     

硫化体系对氯丁橡胶硫化胶性能的影响

研究了金属氧化物（MgO／ZnO）、过氧化物（2,5-二甲基-2,5二叔丁基过氧化己烷,简称双-25）、硫黄、三聚硫氰酸（TCY）4种硫化体系对氯丁橡胶硫化特性、物理机械性能、耐热老化性能和压缩永久变形性能的影响。结果表明：所选4种硫化体系都能较好地硫化氯丁橡胶;双-25和硫黄有较快的硫化速度：TCY和金属氧化物的硫化速度较慢,但二者有很好的抗硫化返原性;硫黄硫化的CR硫化胶拉伸强度较大．但耐热老化性能欠佳;TCY和双-25硫化胶的物理性能能达到金属氧化物的水平．且老化性能较好;金属氧化物有较优的综合力学性能;含TCY的硫化胶有较小高温压缩永久变形。     

双酚AF硫化体系的硫化特性分析

研究了双酚AF硫化体系对氟橡胶硫化特性的影响。研究表明采用双酚AF硫化体系对胶料的加工性能无任何影响；在硫化体系中，BPP（苄基三苯基氯我）对胶料硫化特性的影响较双酚AF更为明显。本文的研究结果为高性能氟橡胶混炼胶的设计提供依据。     

不同硫化体系对NR抗硫化返原性的影响

研究了半有效硫化体系（SEV）、普通硫黄硫化体系（CV）、平衡硫化体系（EC）等对NR硫化特性、力学性能、交联密度的影响。结果表明：不同硫化体系硫化的NR胶料抗返原性从大到小顺序为EC〉SEV2〉SEV1〉CV。SEV2硫化胶力学性能优异,交联密度较大。SEV1和CV硫化胶在过硫化条件下力学性能降低显著。在不同硫化条件下,EC和SEV2硫化胶横向松弛时间t2变化较小,抗返原性较好;SEV1和CV硫化胶横向松弛时间t2变化较大,抗返原性较差。     

过氧化物硫化体系

该硫化体系通常并用了一些硫化助剂，硫化键为碳-碳硫化键，产品的耐热性及压缩永久变形性非常优异，其硫化速度也很快，硫化的效率和程度都很高。但是该体系撕裂强度很差，常需模具硫化（高压蒸汽除外）。常用的过氧化物有：过氧化二异丙苯（DCP）、双叔丁基过氧异丙基苯等，用量均为2到4份。     

不同促进剂对NR平衡硫化体系的影响

研究了促进剂的种类，促进剂并用及硫化温度等条件对平衡硫化体系（ＥＣ）硫化天然橡胶（ＮＲ）的影响。结果表明，噻唑类促进剂具有较低的硫化返原率，尤其是促进剂ＤＭ，在１３０～１７０℃的硫化温度范围内，硫化２小时的硫化返原率均为０；当促进剂ＮＯＢＳ或ＣＺ与ＤＭ并用时，可缩短正硫化时间；当ＤＭ摩尔分数分别为４０％和５０％左右时，不仅使硫化２小时的硫化返原率为０，而且可使３００％定伸应力保持恒定；以ＮＯＢＳ或ＣＺ为主促进剂时，正硫化时具有较高的拉伸强度和撕裂强度，但硫化２小时时的降低幅度比ＤＭ大。     

氯化丁基橡胶三嗪硫化体系硫化机理探讨

在交替变更2-正丁氨基-4,6-二巯基均三嗪（硫化剂DB）和氧化镁用量的情况下,考察了二者配合硫化氯化丁基橡胶的硫化特性和物理机械性能,并进行了傅里叶变换红外光谱和热重的分析,探讨了其硫化机理。结果表明,硫化剂DB和氧化镁配合可以很好地硫化氯化丁基橡胶,做到“无锌硫化”。在氧化镁用量固定的情况下,1.0～1.5份（质量）的硫化剂DB用量比较合适;在该硫化体系中氧化镁能起到改善焦烧、延迟硫化的作用。该交联反应的特点在于烯丙基键合的氯原子参与反应,三嗪硫醇的巯基与烯丙基氯反应并脱出氯化氢,形成碳硫键交联网络,氧化镁作为酸受体参与硫化反应。     

复合硫化体系在EPDM胶料中的应用

介绍了一种复合硫化体系（3DCP＋2TE）,采用该复合物体系硫化三元乙丙橡胶（EPDM）胶料时,可以提高其物理性能及耐老化性能,使EPDM具有良好的综合性能。     

氟橡胶中双酚AF硫化体系的硫化特性分析

研究了双酚AF硫化体系对氟橡胶硫化特性的影响。结果表明：双酚AF硫化体系中硫化剂及促进剂用量的变化对胶料的加工性能无任何影响；在硫化体系中，BPP（苄基三苯基氯化磷）对胶料友化特性的影响较双酚AF更为明显。     

交联键类型对硫化丁苯橡胶拉伸应力松弛行为的影响

利用两相模型讨论了不同硫化体系的硫化丁苯橡胶的应力松弛行为。通过平衡溶胀法求得不同硫化体系中存在的几种不同交联网络结构的含量。普通硫化体系(CV)含有较多的多硫交联键,有效硫化体系(EV)含有较多的单硫交联键,而半有效硫化体系(SEV)的单硫、多硫交联键含量在前两者之间。考察了交联键类型、拉伸速率以及应变对应力松弛行为的影响。结果表明,CV体系的拉伸强度、不可松弛分量都要高于其它2种体系。交联键类型对可松弛分量的影响较小。     

TPI结晶性对硫黄硫化SBR/TPI并用胶性能的影响

分别研究了反式—1,4—聚异戊二烯（TPI）结晶性对普通硫黄硫化体系（CV）和半有效硫黄硫化体系（SEV）硫化的SBR/TPI硫化胶性能的影响。结果表明,SEV体系的硫化胶结晶熔融焓略高。与CV体系相比,SEV体系的硫化试样拉伸强度高。在同一压缩深度下,当TPI用量超过50份后,SEV体系的硫化胶压缩强度高于CV体系的硫化胶。同一并用比时,SEV体系的硫化胶tanδ峰值低于CV体系的硫化胶;随着TPI用量的增加,两种体系的硫化胶tanδ峰值之间的差异逐渐减小。     

Effect of crosslink structures on dynamic mechanical properties of natural rubber vulcanizates under different aging conditions

The effects of crosslink structures on the dynamic mechanical properties (DMPs) of unfilled and carbon black N330‐filled natural rubber (NR) vulcanizates cured with conventional (CV), semiefficient (SEV), and efficient (EV) cure systems and having about the same total crosslink densities were investigated before and after aerobic and anaerobic aging at 100°C. The three unfilled NR vulcanizates cured with the CV, SEV, and EV systems had about the same mechanical loss factor (tan δ) values at about 0°C but showed some apparent differences in the tan δ values in the order EV > SEV > CV at relatively high temperatures of 40–80°C before aging. However, N330‐filled NR vulcanizates gave higher tan δ values than the unfilled vulcanizates and showed little effect of the crosslink types on the tan δ at different temperatures over the glass‐transition temperature (T_g) before aging. Aerobic heat aging increased the T_g and tan δ values of the vulcanizates over a wide range of temperatures from ?80 to 90°C that was mainly due to the changes in the total density and types of crosslinks. The unfilled vulcanizates cured with the CV system showed the greatest change in DMP because of their poor resistance to heat aging. Aerobic heat aging of NR vulcanizates caused a more significant change in the DMP than anaerobic heat aging because of the dominant effect of the oxidative degradation during aerobic heat aging on the main‐chain structure, crosslink structures, and DMPs of the vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 710–718, 2001     

NR/BR/TPI共混物硫化体系的研究

研究了普通硫化体系(CV)、半有效硫化体系(SEV)和有效硫化体系(EV)对NR／BR，TPI共混物(共混比为40／40／20)性能的影响，特别是CV体系中硫黄和促进剂DM用量的影响。结果表明，采用CV体系，NR／BR／TPI共混物的耐疲劳性能等物理性能较好，硫黄用量为3份、促进剂DM用量为1份时，共混物的撕裂强度和耐屈挠性能最好，其它性能也保持在较高水平。配合剂直接加入共混胶中混炼比分别加入3种生胶混炼后再加以混合的方式可获得更好的力学性能，但正硫化时间和焦烧时间缩短。     

Chemical crosslink densit and network structure of natural rubber vulcanizates modified with phosphorylated cardnol prepolymer

The chemical crosslink density (CLD) and network structure of natural rubber (NR) vulcanizates, modified with phosphorylated cardanol prepolymer (PCP), have been studied by equilibrium swelling and other chemical methods. The PCP-modified NR vulcanizates showed lower CLD, as compared to the unmodified NR samples, the decrease being lesser for the semiefficient vulcanization (SEV) system, as compared to the conventional (CV) and efficient (EV) vulcanization system. The superior tensile characteristics of the PCP-modified vulcanizates of the SEV system is presumed to be partly due to the presence of an entangled network structure between the aliphatic segment of PCP and the isoprene chains, as evident from X-ray diffraction studies. The critical role of Zn⁺⁺ions in the crosslinking reactions, especially at higher concentrations of PCP, was evident from the increase in CLD at higher concentrations of ZnO. The reduction in the IR absorption intensity, in the presence of ZnO, indicated the probable complex formation of Zn⁺⁺ions with the phosphate groups of PCP. © 1994 John Wiley & Sons, Inc.     

Cure characteristics and physicomechanical properties of natural rubber modified with phosphorylated cashew nut shell liquid prepolymer—A comparison with aromatic oil

Natural rubber (NR) has been modified with 10 phr each of phosphorylated cashew nut shell liquid (PCNSL) prepolymer and an aromatic oil (spindle oil) in a typical semi-efficient vulcanization (SEV) system. Despite the lower chemical crosslink density, the PCNSL modified NR vulcanizate showed higher tensile strength, elongation at break, thermal stability, and resistances to fatigue failure and thermo-oxidative decomposition, as compared to the vulcanizate containing the same dosage of spindle oil. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 813–818, 1999     

Thermoplastic natural rubber based on polyamide‐12: Influence of blending technique and type of rubber on temperature scanning stress relaxation and other related properties

Thermoplastic natural rubber based on polyamide‐12 (PA‐12) blend was prepared by melt blending technique. Influence of blending techniques (i.e., simple blend and dynamic vulcanization) and types of natural rubber (i.e., unmodified natural rubber (NR) and epoxidized natural rubber (ENR)) on properties of the blends were investigated. It was found that the simple blends with the proportion of rubber ～ 60 wt % exhibited cocontinuous phase structure while the dynamically cured blends showed dispersed morphology. Furthermore, the blend of ENR exhibited superior mechanical properties, stress relaxation behavior, and fine grain morphology than those of the blend of the unmodified NR. This is attributed to chemical interaction between oxirane groups in ENR molecules and polar functional groups in PA‐12 molecules which caused higher interfacial adhesion. It was also found that the dynamic vulcanization caused enhancement of strength and hardness properties. Temperature scanning stress relaxation measurement revealed improvement of stress relaxation properties and thermal resistance of the dynamically cured ENR/PA‐12 blend. This is attributed to synergistic effects of dynamic vulcanization of ENR and chemical reaction of the ENR and PA‐12 molecules. Furthermore, the dynamically cured ENR/PA‐12 blend exhibited smaller rubber particles dispersed in the PA‐12 matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel dynamic vulcanization of polyethylene and ozonolysed natural rubber blends: Effect of curing system and blending ratio

Dynamic vulcanization was studied in terms of the change in α‐relaxation temperatures of the LDPE matrix, morphology, and mechanical properties of LDPE/ozonolysed NR blends which were vulcanized at various blend ratios and with different curing systems, i.e., peroxide and sulfur systems. The ozonolysed NR with M _w = 8.30 × 10⁵ g mol⁻¹ and M _n = 2.62 × 10⁵ g mol⁻¹, prepared by the in situ ozonolysis reaction of natural rubber latex, was used in this study. The significant change in the α‐relaxation temperature of LDPE in the LDPE/ozonolysed NR, dynamically vulcanized using the sulfur system, suggested that sulfur vulcanization of the blend gave a higher degree of crosslink density than using peroxide and corresponded with the improved damping property and homogenous phase morphology. However, the peroxide cured blends of LDPE/ozonolyzed NR gave more improvement of tensile strength and elongation at break than the sulfur cured system. Furthermore, the mechanical properties of tensile strength, elongation at break, and damping were improved by increasing the ozonolyzed natural rubber content in both DCP and sulfur cured blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

交联助剂对过氧化物硫化天然胶乳性能的影响

选用不同的过氧化物硫化体系制得硫化天然胶,在此基础上探讨了不同种类及用量的交联助剂和热处理温度对硫化效果的影响.结果表明:选用BPO过氧化物硫化天然胶时,添加3份DVB交联助剂的硫化天然胶,基本达到了硫黄硫化的基本力学性能;选用过氧化二叔丁基-硫酸亚铁络合物的氧化还原体系,添加3份的SJ-1交联助剂,在80℃以上时,可使硫化天然胶性能进一步提高,拉伸强度相比BPO过氧化物硫化的天然胶增加了近一倍.平衡溶胀试验的结果表明,氧化还原体系制得的硫化胶有最小的平衡溶胀增量和最大的凝胶含量.