EVA/NBR TPV压缩Mullins效应的研究

采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),系统研究了EVA/NBR TPV压缩Mullins效应。结果表明,随着EVA/NBR共混比及压缩应变的增大,TPV压缩Mullins行为趋于显著;当压缩应变一定时,首次循环加载-卸载过程中最大压缩应力、内耗和tanδ均达到最大值,而第2次加载-卸载过程中均发生大幅下降,之后下降趋势逐渐减弱。在相同应变下,EVA/NBR共混比60/40的TPV最大压缩应力、残余变形、内耗、应力软化因子和tanδ均大于共混比40/60的TPV,变化幅度较为明显。     

丁腈橡胶/乙烯-乙酸乙烯共聚物热塑性硫化胶的Mullins效应形成机制及可逆回复

采用动态硫化法制备了丁腈橡胶(NBR)/乙烯-乙酸乙烯共聚物(EVA)热塑性硫化胶(TPV),考察了其压缩Mullins效应及其在不同温度下的可逆回复行为,并与EVA及NBR静态硫化胶进行了对比。结果表明,在单轴循环压缩过程中NBR/EVA TPV及EVA均存在明显的Mullins效应,在一定压缩应变下,第1次加载-卸载的最大压缩应力和内耗出现最大值,第2次循环压缩时则显著降低,之后下降趋势减缓。升高热处理温度,第2次单轴循环压缩时压缩Mullins效应的回复程度增大。在NBR静态硫化胶的单轴循环压缩过程中未观察到明显的Mullins效应。     

撕裂模式下EMA/NBR TPV的Mullins效应及其可逆回复行为

采用动态硫化法制备了乙烯-丙烯酸甲酯共聚物(EMA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),研究其微观相结构、撕裂模式下的Mullins效应及热处理条件下Mullins效应可逆回复行为。结果表明,EMA/NBR TPV的微观相形貌呈现出典型的"海-岛"结构;撕裂模式下EMA/NBR TPV的单轴循环测试过程中可观察到明显的Mullins效应,且随着应变的增加,最大撕裂强度、瞬时残余应变、内耗及阻尼因子均呈现出上升趋势,但应力软化因子随之下降;经过热处理后EMA/NBR TPV的Mullins效应回复程度显著提高,且在100℃的热处理条件下回复效果最佳。     

丙烯腈-丁二烯-苯乙烯三元共聚物/丁腈橡胶热塑性硫化胶的相容及Mullins效应研究

采用动态硫化方法制备丙烯腈 丁二烯 苯乙烯三元共聚物（ABS）/丁腈橡胶（NBR）热塑性硫化胶（TPV）,以氯化聚乙烯（CPE）为相容剂改善其界面相容性,研究CPE用量对TPV物理性能、Mullins效应和微观结构的影响。结果表明：CPE可显著改善ABS/NBR TPV的界面相容性,当CPE用量为6份时,TPV的综合性能较好;TPV在单轴循环拉伸过程中存在明显的Mullins效应,在相同的拉伸比下,TPV的最大应力、内耗能和损耗因子在第1次加载 卸载循环中最大,在第2次循环拉伸时显著下降,但随后下降幅度减小;与未相容TPV相比,相容TPV具有较高的瞬时残余形变、应力软化因子和损耗因子。扫描电子显微镜分析结果表明,相容TPV的断面较为平整,NBR硫化胶粒子均匀分散在TPV的表面。     

撕裂模式下乙烯-丙烯酸共聚物/丁腈橡胶热塑性硫化胶的Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-丙烯酸共聚物(EAA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),对其撕裂强度、微观相结构、撕裂模式下的Mullins效应及热处理条件下的Mullins效应可逆回复行为进行了研究.结果表明,EAA/NBR TPV在EAA与NBR的质量比为40/60时的撕裂强度和应变较高.微观形貌观察可见,EA...     

ABS/NBR热塑性硫化胶压缩Mullins效应及其可逆恢复的研究

研究丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)/丁腈橡胶(NBR)热塑性硫化胶(TPV)的压缩Mullins效应及其可逆恢复。结果表明:NBR粒子均匀分散在TPV表面,其粒径为10~15μm;在循环单轴压缩过程中TPV出现明显Mullins效应,且同一压缩应变下,TPV的最大压缩应力、内耗和损耗因子(tanδ)均在第1次加载-卸载循环时达到最大,在第2次加载-卸载循环时显著下降,此后呈缓慢下降趋势;随着压缩次数增加,TPV的瞬时残余形变和应力软化因子(Ds)增大;随着压缩应变增大,TPV的最大压缩应力、瞬时残余形变、内耗和tanδ均显著增大,Ds减小;随着热处理温度升高,TPV在第2次循环压缩时最大压缩应力的恢复程度增大,热处理温度为110℃时,TPV压缩Mullins效应的恢复效果最佳。     

ZDMA增强EVA/NBR TPV的压缩应力松弛及其可逆回复

以甲基丙烯酸锌(ZDMA)为补强剂填充丁腈橡胶(NBR),采用动态硫化法制备了系列乙烯-醋酸乙烯共聚物(EVA)/NBR/ZDMA热塑性硫化胶(TPV),研究了其微观结构及压缩应力松弛行为,并研究了ZDMA用量及热处理温度对TPV压缩应力松弛可逆回复的影响。结果表明,随着ZDMA用量的增加,TPV的应力松弛现象趋于明显,但可逆回复能力增强;提高热处理温度,TPV的压缩应力松弛可逆回复程度显著提高,且在70℃时TPV的压缩应力松弛可逆回复程度较高;FE-SEM研究表明,ZDMA增强TPV中,NBR橡胶相的尺寸明显细化。     

炭黑增强SBR/EVA/HIPS热塑性硫化胶的性能研究

采用动态硫化法制备了炭黑增强丁苯橡胶(SBR)/乙烯-醋酸乙烯共聚物(EVA)/高抗冲聚苯乙烯(HIPS)热塑性硫化胶(TPV),研究了炭黑对TPV应力松弛及粘弹行为和力学性能的影响。结果表明,在TPV分散相SBR中加入炭黑,力学性能显著改善,应力松弛残留应力增大;频率扫描模式下,储能模量下降,损耗因子增加;应变扫描模式下,TPV表现出明显的Payne效应,且炭黑填充使Payne效应弱化。     

炭黑增强EVA/CMTPV的性能研究

以炭黑作补强剂,采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/氯化聚乙烯(CM)热塑性硫化胶(TPV),并研究了力学性能、Mullins效应和微观相结构。结果表明,当EVA/CM/CB质量比在40/60/6~40/60/24范围内时,TPV动态硫化产物表现出良好的综合性能。单轴循环拉伸实验表明,TPV存在明显的Mullins效应,即第1次拉伸后就表现出明显的应力软化现象;在拉伸比固定不变时,TPV最大应力随拉伸次数的增加而下降,残留应变逐渐增大。SEM观察结果表明,动态硫化EVA/CM/CB TPV的拉伸断面较为平坦,表现出良好的弹性回复能力,刻蚀样品表面均匀分散着CM硫化胶粒子,其平均尺寸为2μm左右。     

EVA/NBR TPV的压缩Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),并对其微观结构、压缩Mullins效应及其在不同温度下的可逆回复程度进行了研究,通过模型构建探讨了压缩Mullins效应的形成及其可逆回复机制。结果表明,在单轴循环压缩过程中,TPV存在明显的Mullins效应,在压缩应变一定的条件下,第1次加载-卸载时最大压缩应力、内耗及tanδ均出现最大值,第2次循环压缩时则显著降低,之后下降趋势减缓;提高热处理温度,重加载时最大压缩应力的回复程度增大,且在70℃热处理条件下Mullins效应的可逆回复效果最佳。FE-SEM表明,NBR橡胶相以不规则形状均匀分散于刻蚀样品表面。     

撕裂模式下乙烯-乙酸乙烯酯共聚物/氯丁橡胶热塑性硫化胶的Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-乙酸乙烯酯共聚物（EVA）/氯丁橡胶（CR）热塑性硫化胶（TPV）,对其微观形貌、撕裂强度、撕裂模式下的Mullins效应、热处理后的可逆回复行为及其机制进行了研究。结果表明,EVA/CR TPV橡塑质量比为30/70时其撕裂模式下的应变和撕裂强度较高,橡胶相与树脂相呈“海-岛”结构;撕裂模式下EVA/CR TPV的单轴循环测试中表现出明显的Mullins效应,增大应变时,其最大撕裂强度、瞬时残余应变、内耗值和阻尼因子均增加,但应力软化因子趋于下降;随着热处理温度的上升,Mullins效应的可逆回复效果获得改善,且温度为70℃时其可逆回复行为最好。     

有机蒙脱土/丁基橡胶/聚丙烯热塑性硫化胶的制备与性能

采用动态硫化法制备了有机蒙脱土（OMMT）/丁基橡胶（IIR）/聚丙烯（PP）热塑性硫化胶（TPV）,考察了OMMT的用量和IIR/PP的质量比对TPV的物理机械性能、动态力学性能及热性能的影响。结果表明,当OMMT的用量为20份时,TPV的物理机械性能较佳,Payne效应最弱,OMMT均匀地分布在基体中,阻尼性能较好,有效阻尼温域较大。OMMT对PP的结晶行为有促进作用,OMMT加入量越多,复合体系的结晶温度越高。当IIR/PP的质量比为60/40时,Payne效应较弱,体系中IIR、PP及OMMT之间的相容性较好。     

Stress softening of NR reinforced by in situ prepared zinc dimethacrylate

The stress softening effect of nature rubber (NR) reinforced by in situ prepared zinc dimethacrylate (ZDMA) was studied. Degree of stress softening effect (Ds) in the 4th stress–strain cycle of the NR with 10 phr (parts per hundreds of rubber) ZDMA was only 2.23 (strain = 100%), whereas it reached to 59.98 at 50 phr ZDMA (strain = 200%). The stress softening effects of carbon black filled into NR, and compared with the ZDMA effect, was also studied here. Mooney–Rivlin semiempirical equation was introduced here to analysis the stress–strain behavior of the NR vulcanize filled with in situ prepared ZDMA, and the results showed that the ZDMA/NR system has an obvious Payne effect which is in good agreement with the stress softening effect. Crosslink density analysis indicated a high ionic crosslink density in the NR filled with high content ZDMA, which contributed to the low elastic recovery of the stress softening. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

低硬度CM／EVA TPV的制备及性能

采用动态硫化法制备了氯化聚乙烯橡胶（CM）／乙烯一醋酸乙烯共聚物（EVA）热塑性硫化胶（TPV）,对其力学性能和动态粘弹行为进行了研究。结果表明：在实验范围内,动态硫化CM／EVATPV呈现出典型弹性体软而韧的应力一应变行为,当CM／EVA的共混质量比在80／20～60／40之间时,所制备的低硬度TPV表现出了良好的综合性能。橡胶加工分析仪（RPA）的研究表明,随着扫描频率的增加,CM／EVATPV的储能模量呈线性增长趋势,损耗因子则呈下降趋势;随着应变的增加,TPV表现出明显Payne效应,储能模量发生大幅度下降,损耗因子在应变大于10．O％后急剧增加。     

Dynamically vulcanized acrylonitrile–butadiene–styrene terpolymer/nitrile butadiene rubber blends compatibilized by chlorinated polyethylene

Thermoplastic vulcanizates (TPVs) based on acrylonitrile–butadiene–styrene (ABS)/nitrile butadiene rubber (NBR) blends were prepared by dynamic vulcanization and then compatibilized by chlorinated polyethylene (CM). The effects of CM compatibilizer on the mechanical properties, Mullins effect, and morphological and dynamic mechanical properties of the TPVs were investigated systematically. Experimental results indicated that CM had an excellent compatibilization effect on the dynamically vulcanized ABS/NBR TPVs. Mullins effect results showed that the compatibilized ABS/NBR TPV had relatively lower internal friction loss than the ABS/NBR TPV, indicating the improvement of elasticity. Morphology studies showed that the fracture surfaces of ABS/CM/NBR TPVs were relatively smoother, indicating the improved elastic reversibility. DMA studies showed that the glass to rubber transition temperatures of ABS and NBR phases were slightly shifted toward each other with the incorporation of CM compatibilizer, which indicates the improvement of the compatibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40986.     

炭黑增强氯丁橡胶硫化胶压缩Mullins效应的强化

研究了炭黑增强氯丁橡胶硫化胶的力学性能和压缩Mullins效应的强化效应,探讨了炭黑用量对其压缩Mullins效应的增强机制。结果表明,炭黑增强后的氯丁橡胶硫化胶的屈服强度和模量均得到明显提高,且力学性能在炭黑用量为30份(质量)时达到最佳;在单轴循环压缩过程中,随着炭黑用量的增加,氯丁橡胶静态硫化胶的Mullins效应不断增强,并且在给定的压缩应变下,其最大压缩应力在首次加载-卸载循环压缩时达到峰值,在随后的4次循环压缩中仅发生不同程度的下降。此外,提高炭黑用量及增大压缩应变均可明显增强氯丁橡胶硫化胶的Mullins效应。     

In situ reactive compatibilization and reinforcement of peroxide dynamically vulcanized polypropylene/ethylene‐propylene‐diene monomer tpv by zinc dimethacrylate

This work demonstrates an approach of in situ reactive compatibilization between polypropylene (PP) and ethylene‐propylene‐diene monomer (EPDM) by using ZDMA as a compatibilizer and, simultaneously, as a very strong reinforcing agent. With 7phr ZDMA in the PP/EPDM (30/70, w/w) thermoplastic vulcanizate (TPV), the tensile strength and elongation at break were increased from 5.3 MPa and 222% up to 11.2 MPa and 396%, respectively. Increasing the PP concentration further improved mechanical properties of the TPVs with ZDMA. This tremendous reinforcing as well as the compatibilization effect of the ZDMA was understood by polymerization of ZDMA and ZDMA reacting with EPDM and PP during peroxide induced dynamic vulcanization. A peculiar nano‐composite structure that the crosslinked rubber particles were “bonded” by a transition zone which containing numerous of nano‐particles with dimensions of about 20–30 nm was observed from transmission electron microscopy (TEM). Scanning electron microscopy (SEM) results showed that increase of PP/EPDM ratio reduced the size of crosslinked EPDM particles. Moreover, we found that the ZDMA reinforced EPDM particles resulted in a higher tan δ peak temperature for EPDM phase and built “filler‐filler”‐like networking in the PP melt. POLYM. COMPOS. 34:1357–1366, 2013. © 2013 Society of Plastics Engineers     

Carbon black reinforced thermoplastic vulcanisates based on ethylene–vinyl acetate copolymer/styrene–butadiene rubber blends

Thermoplastic vulcanisates (TPVs) based on ethylene–vinyl acetate copolymer (EVA)/styrene–butadiene rubber (SBR) blends were prepared by dynamic vulcanisation, with the TPVs being reinforced by carbon black (CB). Experimental results indicated that the mechanical properties of dynamically vulcanised EVA/SBR blends were enhanced remarkably by the incorporation of CB. Morphology study showed that the SBR particles with average diameter of 20?μm were dispersed evenly on the etched surface of EVA/SBR/CB TPVs. The Mullins effect could be observed in the stress–strain curves of EVA/SBR TPVs and EVA/SBR/CB TPVs during the uniaxial loading–unloading cycles. Compared with EVA/SBR TPVs, CB reinforced EVA/SBR TPVs had the relatively higher stress, residual deformation and internal friction loss.     

Dynamic stress‐stiffening of carbon black‐filled vulcanizates

Dynamic stress‐stiffening was investigated under relatively low deformation for the vulcanizates reinforced with carbon black. When dynamic strain sweep with fixed strain amplitude was imposed on samples, storage modulus and loss modulus were significantly increased and loss tangent and loss compliance remained unchanged. It was found that stress‐stiffening effect showed a strong dependence on aging time, frequency, as well as oscillatory strain magnitude. At 60°C, the strain‐aged vulcanizate produced a significant stress‐stiffening effect whereas the material hardening was not observed at 0°C. The increased Payne effect after cyclic deformations can be destroyed partially by dynamic strain sweeps. These features are quite different from the Mullins effect and dynamic stress‐softening effect in filled rubbers. We interpreted this character of filled vulcanizates in much developed carbon black agglomerates and other possible superstructures. The results provide new insight into understanding the relationship between the rolling resistance of tires and lab‐tested dynamic property. POLYM. ENG. SCI., 59:1743–1752, 2019. © 2019 Society of Plastics Engineers