Replacement of virgin rubbers by waste ground vulcanizates in blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene fluoride terpolymer

This study reports the results of investigations on blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene fluoride terpolymer and the effects of replacement of silicone rubber and/or fluororubber in their 50/50 blend by the respective vulcanizate powders of known compositions. To simulate the aging condition of factory wastes, the silicone rubber or fluororubber vulcanizates were aged for 72 h at 200°C and then converted into powder by mechanical grinding. The fluororubber vulcanizate powder (FVP), mostly spherical in shape with average diameter varying between 2 and 10 μm, exists in a highly aggregated state displaying chainlike structures that, however, break down during blending with virgin rubbers. The silicone rubber vulcanizate powder (SVP) is irregular in shape, with larger particles in the range of 30–100 μm, and the smaller particles exist in highly aggregated chainlike structures, as in the case of FVP, which break down during milling to mostly spherical particles of 2–10 μm in diameter. Measurements of physical properties reveal that the blends of silicone rubber and fluororubber are technologically compatible. SEM photomicrographs of THF‐etched samples show the biphasic structure of the blends, in which the fluororubber forms the dispersed phase in a continuous silicone rubber matrix of lower viscosity. Replacement of silicone rubber in the 50/50 silicone rubber/fluororubber blend by its vulcanizate powder (SVP) increases the Mooney viscosity, but replacement of fluororubber in the blend by its vulcanizate powder (FVP) has little effect on the Mooney viscosity. Monsanto rheometric studies reveal that replacement of silicone rubber by SVP or fluororubber by FVP in the 50/50 silicone rubber/fluororubber blend increases the minimum rheometric torque but decreases the maximum torque, and the effect is more pronounced in the case of SVP. Furthermore, the replacement of silicone rubber in the blend by SVP causes a decline in the physical properties (25% replacement causing about 10% decline in properties, for example), whereas even 75% replacement of fluororubber by FVP has little effect on the physical properties. When both silicone rubber and fluororubber are partially replaced by SVP and FVP in the same blend, properties of the resulting blend composition are controlled more by SVP incorporation, whereas fluororubber replacement has only a marginal effect on blend properties. It is evident from dynamic mechanical spectra that the blends are immiscible in all compositions and addition of SVP or FVP does not affect the glass–rubber transitions of the constituent polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2326–2341, 2001     

Effects of blend ratio and vulcanizate powders on the processability of silicone rubber/fluororubber blends

While silicone rubber has a much lower shear viscosity than that of fluororubber, the viscosity of silicone rubber/fluororubber blends is closer to that of silicone rubber. All rubber compositions show pseudoplastic behavior. While the viscosity of a 50/50 silicone rubber/fluororubber blend increases on replacement of the silicone rubber by silicone rubber vulcanizate powder (SVP), the effect of fluororubber replacement by the corresponding fluororubber vulcanizate powder (FVP) on the shear viscosity is less pronounced. The difference in viscosity between SVP‐replaced silicone rubber and FVP‐replaced fluororubber becomes less prominent at higher shear rates. Fluororubber exhibits a higher extrudate die swell than that of silicone rubber. The die swell of the silicone rubber/fluororubber blends is higher than are the figures obtained by the additivity rule. Replacement of constituent rubbers in the blend by the corresponding vulcanizate powders causes an increase in the die swell. While the silicone rubber extrudate surface is smooth, the fluororubber extrudate shows melt fracture. The extrudate surfaces of the silicone rubber/fluororubber blends are similar to that of the silicone rubber extrudate. Replacement of constituent rubbers by the corresponding vulcanizate powders increases the roughness of the extrudate surface, which is more prominent in the case of silicone rubber replacement by SVP. SVP can replace 50% of silicone rubber and FVP can replace 75% of fluororubber in the 50/50 silicone rubber/fluororubber blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2377–2387, 2003     

Effects of waste ground fluororubber vulcanizate powders on the properties of silicone rubber/fluororubber blends

We prepared fluororubber (FKM) vulcanizate powder (FVP) via cryogenic grinding of the FKM commonly used in automobiles and assessed the particle size distribution of the resulting powder. We also prepared silicone rubber (SR)/FKM blends at a ratio of 25/75. Varying amounts of FKM were replaced with equal amounts of FVP within the range of 5–40 wt%, and the physical properties of the resulting SR/FKM/FVP blends were investigated and compared. The TGA curves of the SR/FKM/FVP blends obtained during the thermal property investigations indicated that pyrolysis of SR occurred within two temperature ranges, and that the SR/FKM/FVP blends with 5 wt% FVP demonstrated the highest thermal stability. The storage modulus (E') and loss modulus (E″) of the SR/ FKM/FVP blends increased as the FVP content increased. In the SR/FKM/FVP blends with 5 and 10 wt% FVP, very typical elastic‐deformation behavior was observed. On the contrary, in 40 wt% FVP, the rubber properties disappeared. The mean particle size of FVP was 41.75 μm, and particle size distribution measurements of the SR/FKM/FVP blends suggest particle coexistence such that FVP was condensed and separated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Recycling of silicone rubber waste: Effect of ground silicone rubber vulcanizate powder on the properties of silicone rubber

The silicone rubber vulcanizate powder (SVP) obtained from silicone rubber by mechanical grinding exists in a highly aggregated state. The particle size distribution of SVP is broad, ranging from 2 µm to 110 µm with an average particle size of 33 µm. X‐ray Photoelectron Spectroscopy (XPS) and Infrared (IR) Spectroscopy studies show that there is no chemical change on the rubber surface following mechanical grinding of the heat‐aged (200°C/10 days) silicone rubber vulcanizate. Addition of SVP in silicone rubber increases the Mooney viscosity, Mooney scorch time, shear viscosity and activation energy for viscous flow. Measurement of curing characteristics reveals that incorporation of SVP into the virgin silicone rubber causes an increase in minimum torque, but marginal decrease in maximum torque and rate constant of curing. However, the activation energy of curing shows an increasing trend with increasing loading of SVP. Expectedly, incorporation of SVP does not alter the glass‐rubber transition and cold crystallization temperatures of silicone rubber, as observed in the dynamic mechanical spectra. It is further observed that on incorporation of even a high loading of SVP (i.e., 60 phr), the tensile and tear strength of the silicone rubber are decreased by only about 20%, and modulus dropped by 15%, while the hardness, tension set and hysteresis loss undergo marginal changes and compression stress‐relaxation is not significantly changed. Atomic Force Microscopy studies reveal that incorporation of SVP into silicone rubber does not cause significant changes in the surface morphology.     

Recycling of EPDM waste. I. Effect of ground EPDM vulcanizate on properties of EPDM rubber

Processing, cure characteristics, and mechanical properties of EPDM rubber containing ground EPDM vulcanizate of known composition were studied. Mooney viscosity increases and Mooney scorch time decreases by the addition of the ground vulcanizate. At higher loadings of the ground rubber, the maximum rheometric torque decreases. On addition of ground waste, stress–strain properties and tear resistance increase, whereas heat buildup marginally increases, resilience marginally decreases, low‐strain modulus remains constant, and abrasion resistance decreases. The interplay between the filler effect of the ground EPDM and the crosslink density changes of the EPDM matrix is believed to be the reason for the variation in mechanical properties. It is believed that sulfur migration occurs from the raw EPDM matrix (R‐EPDM) to the ground waste EPDM (W‐EPDM) particle while accelerator migration occurs from W‐EPDM to R‐EPDM. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3293–3303, 2001     

辐射预硫化炭黑/白炭黑天然橡胶胶料性能对比研究

对炭黑和白炭黑分别填充的天然橡胶(NR)胶料进行电子辐射预硫化,研究辐射预硫化对胶料的结合胶含量、门尼粘度和硫化特性及硫化胶的物理性能和动态性能的影响。结果表明,辐射预硫化能提高胶料的结合胶含量、门尼粘度和硫化速度,对两种硫化胶的应力应变、生热和磨耗等性能产生不同的影响,并能显著抑制填料在橡胶基体内网络结构的形成,降低胶料的滞后损失。     

HMPIB分子量及配比对IIR/HMPIB体系力学性能的影响

本文研究了HMPIB分子量及用量对IIR/HMPIB共混橡胶力学性能的影响。结果表明：HMPIB能够降低门尼粘度,随用量的增加门尼粘度逐渐降低;饱和的HMPIB使IIR/HMPIB体系有效交联密度降低,进而影响硫化胶的力学性能。扯断伸长率及撕裂强度都有增加,且增幅与HMPIB的用量及分子量成正比;较高分子量的HMPIB对硫化胶拉伸强度是有利的;定伸应力随HMPIB用量的增加呈下降趋势。在交联密度水平相当的前提下,IIR/HMPIB体系比纯IIR硫化胶有更大的拉伸强度、撕裂强度和扯断伸长率,定伸应力相当或稍有下降,显示了HMPIB对IIR有一定的增强作用。     

国产丁戊橡胶与顺丁橡胶的加工应用性能对比研究

通过与BR的对比,研究了国产丁戊橡胶(BIR)的加工性能、硫化特性、物理性能,并探讨了BIR与BR在胎面胶中的加工应用性能差异。结果表明,BIR硫化速度快,门尼粘度低,加工性能好;BIR硫化胶撕裂强度高,压缩温升低,耐疲劳性好。NR/SBR/BIR并用体系胎面胶硫化速度快,加工性能好;硫化胶的撕裂强度、耐疲劳、抗湿滑等性能均优于NR/SBR/BR并用体系。     

天然橡胶/顺丁橡胶/丁苯橡胶自润滑喷蜡橡胶材料的性能

在天然橡胶(NR)/顺丁橡胶(BR)/丁苯橡胶(SBR)为基体的自润滑喷蜡橡胶材料中加入芥酸酰胺,考察芥酸酰胺作为润滑剂时对NR/BR/SBR自润滑喷蜡橡胶材料的硫化特性、力学性能、门尼黏度、摩擦系数及耐老化性能的影响。结果表明,与未加芥酸酰胺的胶料相比,当芥酸酰胺用量为10份时,胶料转矩减小,焦烧时间和正硫化时间缩短,扯断伸长率从388%增加至523%,拉伸强度降低了21.36%,邵尔A硬度、压缩永久变形分别下降5.56%和8.74%,动、静摩擦系数分别减小23.46%和24.82%,门尼黏度降低20.89%,耐热氧老化性能下降。硫化胶拉伸100%停放5 min后,表面出现明显的白色润滑膜,胶料流动性变好,各组分分散得更均匀,断面更光滑。     

多功能助剂KLF-808在全钢载重子午线轮胎中的应用

试验研究多功能助剂KLF-808在全钢载重子午线轮胎中的应用效果。结果表明,在全钢载重子午线轮胎胎面胶、下三角胶和外护胶中加入KLF-808,可以降低胶料的门尼粘度,提高胶料的抗硫化返原性能,降低硫化胶的压缩生热,提高成品轮胎的耐久性能;在胎面胶中加入KLF-808,可以提高硫化胶的耐磨和抗刺扎性能。     

SIBR生胶门尼粘度对胶料性能的影响

研究不同门尼粘度的集成橡胶(SIBR)混炼胶和硫化胶的各项性能,并与溶聚丁苯橡胶(SSBR1204)进行对比.结果表明,适当提高SIBR生胶的门尼粘度,可以在不影响胶料加工性能的前提下,提高混炼胶强度,同时硫化胶的物理性能和动态力学性能也普遍得到改善.高门尼粘度的SIBR综合性能较理想,与SSBR1204相比并无显著差异.     

环保芳烃油对溶聚丁苯橡胶工艺性能的影响

研究几种环保芳烃油（TDAE）对溶聚丁苯橡胶（SSBR）工艺性能的影响,并与芳烃油（DAE）进行对比。试验结果表明：以TDAE替代DAE,随着油品运动粘度或芳烃含量的增大,SSBR生胶及混炼胶的门尼粘度先减小后增大;胶料的门尼焦烧时间延长,硫化速度减慢,t90随油品芳烃含量的减小而逐渐延长,自粘性较好,出口膨胀率减小;硫化胶的物理性能无明显差异。     

Research progress on compounding agent and mechanical test method of fluororubber

Fluororubber (FKM) materials have excellent mechanical properties, and are widely used in automotive and aerospace fields. As fluorine rubber is a typical representative of new special rubber, the formula and mechanical test method of fluorine rubber have become one of the important issues at present. Multi-factor optimization of fluororubber compound plays an important role in the mechanical properties of FKM. Based on the introduction of new materials in FKM compounding agents (reinforcing agent, softening plasticizer, anti-aging agent, accelerator, vulcanizing agent, auxiliary agent and filler), this paper focuses on the research progress of characterization methods and mechanical properties of the composite materials combined with FKM.     

国产钕系BR的综合性能

将国产钕系顺丁橡胶（ＮｄＢＲ）与国外同类产品和国产镍系顺丁橡胶ＮｉＢＲ进行了基本性能的对比。与国产ＮｉＢＲ相比、ＮｄＢＲ显示了链结构规整性与相绎分子质量较高、相对分子质量分布较窄、加工性能稍差、自粘结性能与生胶强度较高、硫经胶拉伸强度的固弹性高、疲劳生热低、疲劳生热低、动态力学性能优良、抗湿滑性与滚动阻力之间具有最佳平衡等特点,综合性能比ＮｉＢＲ优良。国产ＮｄＢＲ的性能与国外轴类产品基本相近,其中     

加工助剂在白炭黑胎面胶中的应用

研究加工助剂莱茵塑分ST和GT对溶聚丁苯橡胶(S-SBR)／BR胶料以及莱茵塑分ST用量对S-SBR／乳聚丁苯橡胶(E-SBR)／BR胶料性能的影响。结果表明，在S-SBR／BR胶料中加入莱茵塑分ST和GT，可以降低胶料的门尼粘度，改善胶料的加工性能，对硫化胶的物理性能影响不大。在S-SBR／E-SBR／BR胶料中加入莱茵塑分ST，可以显著改善胶料的加工性能，提高硫化胶的定伸应力和耐热老化性能；莱茵塑分ST用量为4份时，硫化胶的动态力学性能最佳。     

门尼粘度及支化程度对三元乙丙橡胶性能的影响

通过无转子硫化仪、橡胶加工分析仪、核磁交联密度仪等分析手段研究三元乙丙橡胶(EPDM)的门尼粘度、长链支化程度对过氧化物硫化EPDM的硫化特性及其硫化胶性能的影响。结果表明,门尼粘度的增加,有助于交联密度和硫化速率的提高,横向弛豫时间不断减小。高支化程度对EPDM胶料硫化速度不利。EPDM门尼粘度越高,初始储能模量G′0越大,储能模量迅速下降的临界应变值越小;不同长链支化度的EPDM硫化胶的储能模量大致相等,但长支化链的损耗因子值相对较高。门尼粘度对EPDM硫化胶拉伸强度变化影响较小;而长链支化程度的提高,使硫化胶拉伸强度和断裂伸长率略微降低。     

贮存烟胶片加工性能研究

采用红外光谱、门尼粘度测定、橡胶加工分析等技术分析了长期自然贮存烟胶片的结构和加工操作性能,测定了硫化胶老化前后的力学性能.长期贮存后,烟胶片的分子链之间发生交联和氧化降解,导致门尼粘度、凝胶含量上升,加工操作性能下降,并且老化前后力学性能显著下降.     

不同粒径胶粉的成分分析及在胎面胶中的应用

通过热重法和红外光谱分析及测定硫含量和粒径分布等方式对用超低温粉碎法制备的不同粒径胶粉的成分进行了分析,并开展了其在商用车轮胎胎面胶中的加工应用研究.结果表明,4种不同胶粉中的挥发分、有机物、炭黑和灰分含量均差别较小,其中有机物质量分数在61％～65％之间,炭黑质量分数在28％～30％之间,含硫质量分数在2％左右,粒径...     

均匀剂A78在工业车辆轮胎胎面胶中的应用

试验研究均匀剂A78在工业车辆轮胎胎面胶中的应用效果。结果表明,胎面胶配方中加入均匀剂A78,可降低胶料的门尼粘度,提高炭黑的分散性、胶料的挤出工艺性能和硫化胶的物理性能,改善成品轮胎的物理性能和外观质量,并可降低混炼胶成本。     

炭黑改性顺丁橡胶在乘用车子午线轮胎胎侧胶中的应用

通过在乘用车子午线轮胎胎侧胶配方中加入不同的顺丁橡胶,探讨了普通顺丁橡胶、钕系顺丁橡胶和炭黑改性顺丁橡胶对胎侧胶性能的影响。结果表明,用炭黑改性顺丁橡胶所制备混炼胶的门尼黏度较高,焦烧时间缩短,硫化时间延长,最小和最大转矩均增大;硫化胶的定伸应力、拉伸强度和回弹性均升高,60 ℃时的损耗因子下降;成品轮胎的滚动阻力降低。