弹性体增容NR/EPDM共混胶性能的研究

采用动态硫化法制备NR/EPDM/POE热塑性弹性体来增容NR/EPDM共混胶,通过改变增容剂的含量研究NR/EPDM共混胶的力学性能、微观形态性能、耐热性能。结果表明,随着弹性体增容剂的增加,NR/EPDM共混胶的拉伸性能、撕裂性能、硬度都有上升趋势,拉断伸长率无明显变化;在NR/EPDM中添加20份弹性体增容剂,可以达到较高的力学性能和耐热空气、耐臭氧老化性能。     

杜仲胶/天然橡胶并用胶的热氧老化性能

通过改变杜仲胶(EUG)/天然橡胶(NR)的共混比对EUG/NR并用胶的热氧老化性能进行研究。将EUG/NR并用胶在老化箱中进行加速老化。通过机械性能、交联密度、红外分析和热稳定性来评估EUG/NR并用胶的老化性能。结果表明,随着老化时间的增加,EUG/NR并用胶的拉伸强度和断裂伸长率逐渐下降,100%定伸应力、硬度和交联密度逐渐增大;EUG/NR并用胶在老化5d时交联效应占优势,交联反应主要发生在老化过程中;EUG用量为10～20份时,EUG/NR并用胶的抗热氧老化性能并未明显下降。此外,热重分析(TGA)表明,在老化5d时,EUG/NR并用胶在热氧老化过程中分子主链及交联网络并未出现明显的破坏。     

NR硫化胶的动态力学性能

采用无转子流变仪、橡胶加工分析仪、动态热机械分析仪研究了相对分子质量、炭黑用量、炭黑粒径、促进剂含量、氧化锌含量、硬脂酸含量和老化时间对NR硫化胶动态力学性能的影响。结果表明,0℃和60℃左右,低相对分子质量NR硫化胶的损耗因子(tanδ)略大于高相对分子质量NR硫化胶;随着炭黑用量的增加,硫化胶tanδ峰值减小,继续增加炭黑用量,NR硫化胶的炭黑网络结构增强,tanδ不断变大;随着炭黑粒径的增加,NR硫化胶的玻璃化转变温度(T_g)略向高温方向偏移,而处在高弹态后,硫化胶的tanδ随着炭黑粒径的增大而减小。     

天然胶乳中的蛋白质对其热老化性能的影响研究

本文采用超速离心的方法,去除天然橡胶粒子表面保护层蛋白质,通过改变天然橡胶中蛋白质的含量,分析了蛋白质对硫化胶的力学性能和热老化性能的影响,结果表明,在本实验范围内,随着天然橡胶中蛋白质的含量增加,其力学性能和热老化性能逐渐增加.     

NR/EPDM共混胶制备浅色胶料性能研究（轮胎会）

研究了天然橡胶（NR）和乙丙橡胶（EPDM）共混制备浅色胶料的力学性能、耐老化和耐臭氧性能,同时采用弹性体PNE增容NR/EPDM共混胶。结果表明：在NR中并用EPDM,随着EPDM用量的增加,NR/EPDM共混胶力学性能有所降低,耐臭氧老化性能和耐热空气老化性能提高;使用一定量增容剂PNE替代EPDM能明显改善NR/EPDM共混胶的力学性能和耐屈挠性能;通过对比不同PNE用量共混胶的SEM图像可以看出使用PNE后材料界面变得模糊,通过动态力学性能分析可知,在NR/EPDM共混胶中加入增容剂后损耗因子的两个tanδ峰值逐渐靠近,当PNE的份数为40时tanδ峰值由两个变为一个,界面的模糊和tanδ峰值的减少说明增容剂改善了两种橡胶的相容性。     

N,N′-间苯基双马来酰亚胺对天然橡胶性能的影响

本文以硫黄硫化体系为基础,研究了助交联剂N,N′-间苯基双马来酰亚胺(HVA-2)的用量对天然橡胶(NR)性能的影响。结果表明：随着HVA-2含量的增加,硫化胶的热氧老化系数和伸张疲劳系数先增加后下降;随着老化时间的延长,硫化胶的交联密度逐渐增加。适量的HVA-2可以提高天然橡胶的耐热氧老化性能,且当HVA-2含量为1.0份时,硫化胶的综合性能最好。     

聚乙烯醇/天然橡胶共混物的制备及其性能研究

利用环氧化天然胶乳作为界面改性剂,采用胶乳共混法将聚乙烯醇（PVA）溶液同天然胶乳进行混溶,制备了PVA/天然橡胶（NR）的共混物,通过电子万能材料试验机、动态热机械分析仪、热老化箱和臭氧老化箱,研究了共混物力学性能、玻璃化转变温度、老化性能以及耐溶剂抽出性。结果表明,PVA的加入明显提高了NR的撕裂强度和硬度,而共混物的拉伸强度和断裂伸长率随着PVA含量的增加都出现下降的趋势;随着PVA含量的增加,NR的玻璃化转变温度呈现先增加后降低的趋势;随着PVA含量增加,共混物各试样对乙醇的耐抽出能力相差不大,对水的耐抽出能力逐步变弱。热空气老化对材料的力学性能影响明显,而臭氧老化由于时间较短,对材料的力学性能影响不明显。老化实验对材料的性能变化率影响显著。     

NR/EPDM共混胶的制备与性能研究

主要研究了天然橡胶(NR)与三元乙丙橡胶(EPDM)不同并用比对共混胶硫化性能和综合力学性能的影响,并通过动态力学分析仪(DMA)分析了NR与EPDM的相容性。结果表明,随着EPDM用量的增加,共混胶的拉伸强度、撕裂强度和100%定伸应力先下降后升高,拉断伸长率逐渐减少,硬度逐渐增大,并用EPDM后能明显改善NR的耐臭氧老化性能和耐热空气老化性能;动态力学性能分析表明,NR与EPDM相容性差。当NR/EPDM并用质量比为60/40时共混胶综合性能最佳。     

天然橡胶/再生胶共混胶的交联密度与力学性能

对不同天然橡胶(NR)/再生胶(RR)共混比、不同硫磺及轻质碳酸钙含量的NR/RR共混胶的交联密度和力学性能进行分析测试,并对RR的橡胶烃含量、炭黑含量和无机杂质含量进行热失重测试分析。结果表明,随着RR含量和硫磺含量的增加,硫化胶交联密度上升,轻质碳酸钙含量变化对于硫化胶交联密度没有产生规律性的影响。NR/RR共混比为70/30,硫磺用量为2.5份时NR/RR共混胶综合性能最佳。     

甲基丙烯酸锌对NR耐老化性能的影响

研究了助交联剂甲基丙烯酸锌(ZDMA)用量对NR耐热氧老化性能、耐伸张和压缩疲劳老化性能的影响。结果表明,热氧老化或伸张疲劳后的硫化胶,随着ZDMA用量的增加,力学性能保持率先增大后减小。当硫黄用量为1.5份,ZDMA用量为2份时,耐热氧老化性能及耐伸张和压缩疲劳老化性能达到最优。     

Study of tack properties of uncrosslinked natural rubber

The purpose of this study was to better understand the effect of non-rubber substances (mainly proteins and lipids) on adhesion (against glasses) and self-adhesion tack properties of uncrosslinked natural rubber (NR). Various types of NR, with or without non-rubber constituents, were prepared. Synthetic polyisoprene rubber was also used as a reference material. All the rubbers were first characterized by many techniques (FT-IR, DSC, GPC, etc.). Two experimental tests were specially utilized to measure the level of adhesion and self-adhesion: (i) at very short contact times (from a few milliseconds up to 0.1 s) the impact of a pendulum and (ii) for longer contact times (from 0.1 s to a few h) the contact of a probe using a tensile testing machine. The tack energy increased with contact time for all the rubbers studied. Natural rubber which did not contain proteins and lipids exhibited the highest adhesion and self-adhesion tack abilities. In contrast, whole natural rubber, containing both proteins and lipids, showed the lowest tack property. In each case, self-adhesion levels are higher than those of adhesion, presumably due to interdiffusion of macromolecular chains or chain segments at the interface.     

镧配合物对天然橡胶的防老化作用

选用自制的镧配合物,采用常规方法与天然橡胶混合、硫化制得硫化胶,测试了胶料的硫化特性、硫化胶的力学性能,研究了天然橡胶硫化胶的耐热氧老化性能。结果表明:镧配合物的加入,有助于改善天然橡胶的硫化特性;添加镧配合物的硫化胶力学性能有明显提高;硫化胶的热氧老化结果显示,镧配合物的加入对天然橡胶有较好的防老化作用,其防老化效果优于工业常用防老剂4010NA。     

NR／BR／OMMT纳米复合材料的研究（Ⅰ）复合材料的制备及表征

选用自制的3种有机蒙脱土（OMMT）。利用机械共混法制备了天然橡胶／顺丁橡胶／有机蒙脱土（NR／BR／OMMT）纳米复合材料,测试了复合材料的力学性能,研究了复合材料的耐老化和耐溶剂性能。结果表明：3种OMMT对复合材料的补强效果明显不同,其中2#OMMT为最佳．其断裂强度和撕裂强度均提高近1倍,耐老化和耐溶剂性能也最优异。     

黏土/天然橡胶纳米复合材料的制备及性能

利用乳液插层法制备了黏土／天然橡胶纳米复合材料,研究了该复合材料的力学性能、应力应变行为、耐磨性、气体阻隔性和耐老化性能。结果表明,黏土／天然橡胶纳米复合材料与高耐磨炭黑(N330)、白炭黑增强橡胶相比,邵尔A型硬度、定伸应力和撕裂强度较高,拉伸强度相当。黏土、N330以及白炭黑对天然橡胶的拉伸结晶有影响,填料用量对材料拉伸强度的影响存在最佳值。黏土／天然橡胶纳米复合材料具有良好的耐磨性、气体阻隔性和耐老化性能。     

Optimizing natural rubber blends for examination gloves: Vacuum radiation for mechanical strength and solvent barrier

Natural rubber (NR) is emblematic of sustainability compared to synthetic rubber. However, the tradition of adding sulfur as a vulcanization ingredient results in the release of toxic substances and the potential for health issues. In this study, a feasible strategy was proposed to replace sulfur and discover a safe bulk modification process for NR films. The results have shown that the NR particle size was disintegrated to below 10 nm by gamma irradiation. High tension strength up to 24.45 MPa was observed in the vulcanized NR blend film, which could be elongated up to 800% strain after exposure to an optimum dose of 14 kGy. In comparison to commercial NR latex and nitrile gloves, the vulcanized NR/ SIS films exhibited better chemical resistance ability against hexane, methanol, toluene, and acetone, as revealed by the permeation test. The appearance of amorphous regions and highly oriented NR crystallites was observed through transmission electron microscopy. Findings from this study propose the vacuum radiation strategy that can replace conventional vulcanization methods, resulting in NR films with high mechanical and barrier performance. Furthermore, the emission of toxic substances is reduced by this green process, making it practically useful for potential chemical-resistant examination glove applications.     

烷基硫代磷酸锌硫化促进剂对天然橡胶老化性能影响研究

研究了烷基硫代磷酸锌和其他常用硫化促进剂对天然橡胶硫化胶的老化性能的影响.实验表明二异丙基二硫代磷酸锌能赋予天然橡胶硫化胶优良的耐热空气老化性能.     

Graphene/carbon black/natural rubber composites prepared by a wet compounding and latex mixing process

The extensively used latex mixing approach to prepare graphene can improve the graphene dispersion but meets some challenges in the preparation of high content carbon black filled rubber system like a rubber tire. Owing to the high melt viscosity of the rubber/graphene masterbatch, the dispersion of carbon black is not perfect during twin-roll mixing and some aggregates will be formed. Here we proposed a wet compounding process, combined with ultrasonically assisted latex mixing, named as the WCL method to prepare reduced graphene oxide/carbon black/natural rubber (rGO/CB/NR) composites. The morphological observations confirmed that both graphene and carbon black can be evenly dispersed in the rubber composites. The incorporation of rGO also improves the hardness, thermal conductivity and anti-aging properties of the composites. The rGO/CB/NR composites prepared by the WCL method possess better mechanical properties compared to conventional latex mixing. The entanglement-bound rubber tube model was utilised to understand the reinforcing mechanism.     

GMA对天然橡胶/蒙脱土纳米复合材料老化性能的影响

以含双官能团的甲基丙烯酸缩水甘油酯（GMA）加入到天然胶（NR）／改性蒙脱土（EMT）体系中，原位反应制备出具有纳米结构的复合材料，进行了抗热氧老化、抗紫外光老化和抗臭氧老化实验。结果表明，GMA与NR和改性蒙脱土同时发生相互作用，形成的复合网络结构有效提高了复合材料的抗老化性能。     

NR/BR/OMMT纳米复合材料的结构与性能研究及其在轮胎胎面胶中的应用

采用机械混炼法制备了天然橡胶/顺丁橡胶/有机蒙脱土(NR/BR/OMMT)纳米复合材料,并对复合材料的结构与性能进行了表征。OMMT可明显提高橡胶基体的耐油性能和物理机械性能,降低混炼胶的焦烧时间(Ts)和正硫化时间(T90),起到了促进硫化作用。轮胎胎面胶配合显示,OMMT与炭黑并用补强NR/BR共混胶,明显改善其力学性能与耐磨耗性能。     

Natural rubber-clay nanocomposites: Mechanical and structural properties

The mechanical properties of non-vulcanized natural rubber and dialyzed natural rubber-clay nanocomposites have been studied by uniaxial deformations to evaluate the reinforcement efficiency of the clay. We show that while non-rubber molecules contribute to auto-reinforcement, removal of these molecules improves significantly the performance of clay as reinforcement agent. These mechanical properties are discussed in relation to morphological aspects of the clay characterized by TEM and SANS. The nanocomposites prepared by “latex-mixing” with aqueous dispersions of clay are found to contain completely exfoliated clay lamellae in co-existence with tactoids. Improved mechanical properties of the nanocomposites can be modeled by the high aspect ratio of exfoliated clay platelets coupled with immobilized rubber matrix. Interestingly, presence of tactoids does not appear to compromise the excellent reinforcement properties of the exfoliated platelets. At high deformations, strain-induced alignment of the clay exhibits anisotropic scattering, with anisotropy increasing with clay concentration and stretching.