单甲基丙烯酸锌改性氢化丁腈橡胶老化过程的力学性能演变及其老化动力学

以单甲基丙烯酸锌(HZMMA)为反应型增强剂,制备了HZMMA改性的氢化丁腈橡胶(HNBR)复合材料,研究了无氧、高温条件下HNBR复合材料老化过程的力学性能演变、老化行为及其老化动力学。结果表明,在180℃和200℃的老化温度下,老化前期HNBR/N 990/HZMMA、HNBR/HZMMA复合材料的拉伸强度有所增加,出现极值现象;随着老化时间的延长,材料的拉伸强度呈现逐渐下降的趋势,HNBR/HZMMA复合材料的拉伸强度下降较为缓慢。建立了HNBR/HZMMA复合材料的老化动力学模型,依此模型预测该材料在150℃下的使用寿命超过3年,HNBR/HZMMA复合材料具有优异的耐热老化性能。     

单甲基丙烯酸锌对HNBR复合材料的增强行为研究

以单甲基丙烯酸锌作为补强剂,采用机械混炼法制备了ZMMA/HNBR纳米复合材料,研究了单甲基丙烯酸锌对氢化丁腈橡胶的补强效果,用热失重分析(TG)、差失扫描热量分析(DSC)及材料拉力机等测试方法对复合材料的结构和性能进行了表征测试。实验结果表明,随着ZMMA用量的增加,复合材料的焦烧时间和正硫化时间均呈减少趋势,橡胶复合材料的交联密度逐渐增加,与高分子拉伸取向行为关联不大100%定伸强度和撕裂强度均增加,扯断伸长率呈单调降低。当ZMMA用量为30 phr时,HNBR复合材料的拉伸强度出现最大值。同时,ZMMA聚合物的存在导致材料的最快分解温度和玻璃化转变温度向高温移动,提高了HNBR复合材料的热稳定性。     

氟橡胶/氢化丁腈橡胶复合材料的相容性、力学性能和热氧老化研究

将氟橡胶与氢化丁腈橡胶以不同比例进行共混,研究了共混体系中氟橡胶用量对相容性、力学性能以及耐老化性能的影响。结果表明,并用比例低于20份时,二者表现出较好的相容性;随着氟橡胶用量的增加,橡胶复合材料的拉伸强度逐渐降低,但与交联效率密切相关的100%定伸强度未出现单调递减现象。相反,当二者质量比为10/90时,100%定伸强度,扯断伸长率和撕裂强度出现峰值,同时耐热氧老化的能力最强。     

单甲基丙烯酸锌对氢化丁腈橡胶复合材料性能的影响

以单甲基丙烯酸锌(ZMMA)为补强剂,采用机械混炼法制备ZMMA/氢化丁腈橡胶(HNBR)纳米复合材料,研究ZMMA对HNBR复合材料结构和性能的影响。结果表明:随着ZMMA用量的增大,复合材料的t10和t90均呈缩短趋势,交联密度逐渐增大,100%定伸应力和撕裂强度增大,拉断伸长率呈减小趋势。当ZMMA用量为30份时,HNBR复合材料的拉伸强度出现最大值。ZMMA均聚物的存在导致材料的最大分解速率温度和玻璃化温度向高温方向移动,提高了HNBR复合材料的热稳定性。     

甲基丙烯酸锌增强氢化丁腈橡胶复合材料的性能

采用甲基丙烯酸锌(ZMMA)为增强剂填充氢化丁腈橡胶(HNBR),研究了ZMMA用量对ZMMA/HNBR复合材料硫化特性、力学性能、热稳定性以及玻璃化转变温度(Tg)的影响。结果表明,随着ZMMA用量的增加,复合材料的焦烧时间和正硫化时间缩短,最大转矩和交联密度提高;复合材料的拉伸强度先升高后下降,撕裂强度和100%定伸应力增大,而扯断伸长率降低。复合材料的Tg随着ZMMA用量的增加逐渐升高;ZMMA的加入提高了复合材料的热稳定性。     

原位合成甲基丙烯酸锌增强氢化丁腈橡胶

用ZnO和甲基丙烯酸(MAA)经原位反应合成了甲基丙烯酸锌(ZDMA),将其作为增强剂用以增强氢化丁腈橡胶(HNBR),研究了ZnO／MAA(摩尔比,下同)、过氧化二异丙苯(DCP)用量和ZDMA用量对硫化胶力学性能的影响。结果表明,当ZnO／MAA为0．8,DCP用量为4份(质量,下同)时,原位合成ZDMA能够显著地提高HNBR的力学性能。随着ZDMA理论生成量的增加,硫化胶的拉伸强度先增加后减少,当ZDMA理论生成量为30份时,硫化胶的最大拉伸强度为47.2MPa．而扯断伸长率保持在393％以上;100％定伸应力随ZDMA理论生成量的增加而增加。经傅里叶变换红外光谱法和广角X光衍射法分析表明,在HNBR混炼过程中,ZnO和MAA可以原位生成ZDMA。     

硫化体系对氢化丁腈胶热氧老化性能的影响

系统研究了不同硫化体系对氢化丁腈胶（HNBR）力学性能和热氧老化性能的影响。结果表明：采用过氧化物/硫磺（S）体系得到的胶料其综合性能优于过氧化物体系得到的胶料,在100份HNBR中加入5份过氧化二异丙苯（DCP）和0.5份S,即DCP与S并用时,硫化胶拉伸强度可以达到23.85 MPa,在160℃×72 h热氧老化后仍可以达到20.99 MPa。热氧老化性能以DCP/S为7/0.5时最为优异。     

氢化丁腈橡胶/氟橡胶复合材料的相容性、力学性能及热氧老化性能

采用过氧化二异丙苯硫化体系将氢化丁腈橡胶(HNBR)与氟橡胶(FKM)进行共混,研究了HNBR/FKM复合材料的相容性、微观形态、力学性能及热氧老化性能。结果表明,在FKM用量低于20份(质量)时共混体系的相容性相对较好。随着FKM用量的增加,复合材料的拉伸强度降低,但100%定伸应力却表现出小幅增大的现象。当HNBR与FKM质量比为90/10时,复合材料的撕裂强度、扯断伸长率和100%定伸应力均出现最大值,并呈现出较好的耐热氧老化性能。     

甲基丙烯酸锌补强氢化丁腈橡胶耐老化性能的研究

试验研究甲基丙烯酸锌（ZDMA）补强氢化丁腈橡胶（HNBR）热空气老化前后的物理性能和动态力学性能。结果表明:随着ZDMA用量的增大,HNBR胶料的t₁₀和t₉₀缩短,M_L和M_H增大,硫化胶的邵尔A型硬度和100%定伸应力增大,拉伸强度和拉断伸长率先增大后减小;经热空气老化后,随着老化时间的延长,HNBR硫化胶的邵尔A型硬度和100%定伸应力增大,拉伸强度和拉断伸长率减小;延长老化时间或增大ZDMA用量,HNBR硫化胶的储能模量和损耗模量增大,损耗因子峰值逐渐减小,损耗模量峰值和玻璃化温度逐渐向高温方向移动。     

Thermal aging on mechanical properties and crosslinked network of natural rubber/zinc Dimethacrylate composites

This article dealt with the relationship between mechanical properties and crosslinked networks of natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) after thermal aging. After thermal aging at the present experimental conditions, the covalent crosslink density showed a decrease all the time, whereas the ionic crosslink density was stable at 80°C but decreased at a higher temperature. The decrease in the total crosslink density after aging indicates the degradation of the crosslinked network. However, an experimental phenomenon observed was that the tensile strength and tear strength increased in a certain degree after aging at 80°C or at a 100°C for a short time. In addition, the thermal stability of the NR/ZDMA composite was evaluated by thermal gravimetric analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Friction properties of graphene reinforced nitrile rubber composites after thermal oxidation aging: Experiment and molecular dynamics simulation

We established friction models for pure NBR, GNS/NBR, and GO/NBR composites through molecular dynamics (MD) simulation. Our study focused on the impact of GNS and GO on the friction properties of nitrile rubber (NBR) composite materials after undergoing thermal oxygen aging. Based on the simulation results, it can be observed that the GNS/NBR and GO/NBR composites' coefficient of friction (COF) decreases by 20.8% and 24.8%, respectively, at 348 K. Additionally, the abrasion rate is reduced by 17.4% and 25.7%, respectively, for the same composites. Adding GNS and GO can effectively improve the friction performance of the NBR composite system, and compared with GNS, GO shows a better enhancement effect. Pure NBR and GO/NBR composite materials were prepared by mechanical blending method, and the friction properties of GO-enhanced NBR composite materials were studied. The experimental results show that the GO/NBR composite material can maintain a low friction and wear coefficient after thermal and oxygen aging. It shows that adding GO can effectively improve the friction properties of NBR composite systems and slow down the weakening effect of aging on the friction properties of NBR composite materials. This is because the GO surface contains wealthy functional groups such as epoxy groups, which enhances the binding strength between the GO and NBR interface so that the GO/NBR composite material exhibits better friction properties and thermal oxygen aging resistance. In addition, the wear surface was characterized by scanning electron microscopy (SEM), revealing the damage mechanism of friction and wear of NBR composite materials.     

Thermal aging of bentonite‐filled ethylene propylene diene monomer composites

Bentonite‐filled ethylene propylene diene monomer (EPDM/Bt) composites were prepared using two roll mill compounding method and the effect of Bt loading on the thermal aging, swelling resistance and crosslink density of EPDM/Bt composites were studied. The effect of in situ addition of different silane coupling agents (SCAs) on the above properties at optimum Bt loading of EPDM/Bt composite was also investigated. Thermal aging test results show that the tensile strength and tensile modulus at 100% elongation (M100) increase initially for 2 days aged composites and decrease slightly after 4 days of aging, meanwhile the elongation at break (E_b) decrease gradually with aging period as compared to the unaged composites. Upon aging, swelling resistance increase initially indicating increased crosslink density of EPDM/Bt composite due to post‐curing and reduced after 4 days of aging due to crosslink destruction and EPDM chain scissioning. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4419–4427, 2013     

Thermal and mechanical properties of chitosan reinforced polyhydroxybutyrate composites

The article reports the results of studies on the effect of chitosan (0, 5, 10, 20, 30, and 40 wt %) on thermal and mechanical properties of poly(hydroxybutyrate) composites. The addition of chitosan causes an increase in the glass transition temperature (T_g) while a decrease in the enthalpy of fusion (ΔH_fus), crystallization (ΔH_cry) and percentage of crystallinity as determined by differential scanning calorimeter (DSC). The thermogravimetric analysis reveals that high amount of chitosan decreases the thermal stability of the composites. The Young's modulus of the composite increases and is high for the composite having 40 wt % of chitosan. Increase in the amount of chitosan decreases the elongation at break and impact strength of composites. Finally, the Young's modulus of the composites has been compared with the theoretical predictions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

SIS热熔压敏胶抗热氧老化研究

采用正交试验设计法对SIS热熔压敏胶的各种原料进行优选,通过对剥离强度、初黏力等重要性能的考察,确定了制备SIS热熔压敏胶的主体材料,找到了制备SIS热熔压敏胶的最佳配方为：SIS：矿物油：PIB：C5石油树脂=100：60：60：140。重点研究了SIS热熔压敏胶的热氧老化问题,通过改变抗氧剂种类、用量及老化时间来研究抗氧体系对SIS热熔压敏胶性能的影响。最终确定了最佳抗氧剂配方为：氧化锌：SIS-1105：环烷油-4010：PIB：C5石油树脂（C-100W）：偶联剂：2246：168=80：100：60：60;140：5：0．5：0．5。     

补强剂填充HNBR胶料的结构和性能

试验研究常规补强剂(炭黑、白炭黑)、蒙脱土(原土、有机蒙脱土)和不饱和羧酸盐(甲基丙烯酸锌、甲基丙烯酸镁)三类补强剂对氢化丁腈橡胶胶料物理性能和热空气老化性能的影响,并用扫描电镜、透射电镜和热重分析等方法对其微观结构进行表征.结果表明,常规补强剂分散均匀,胶料有较好的物理性能,但耐热空气老化性能差国防大学;不饱和羧酸盐在橡胶基体中发生交联接枝反应,补强效果最佳,胶料耐热空气老化性能明显提高;有机改性后的蒙脱土分散性和胶料的物理性能大幅度提高,耐热空气老化性能优异.     

Accelerated aging of elastomeric composites with vulcanized ground scraps

The aim of this work is to study the effect of thermal aging on the mechanical, dynamic‐mechanical, and chemical properties of SBR (styrene‐butadiene rubber) composites filled with SBR industrial rubber scraps. Eight composites with varying proportions (10–80 phr) of the SBR ground scraps (SBR‐r) were prepared and subjected to accelerated aging in an air‐oven. The composites were evaluated, and the results were compared with a control sample (base formulation with 0 phr of SBR‐r), before and after thermal aging. The accelerated aging led to a decrease in the mechanical properties as a result of an increase in the stiffness of the material, related to an increase in the crosslink density. However, these properties were not affected by the addition of rubber scraps up to 50 phr, either before or after aging. The increase in the glass transition temperature of the composites after aging, measured using dynamic mechanical analysis, confirmed the occurrence of a postcrosslinking process. Fourier transform infrared spectroscopy and crosslink density revealed that the aging mechanism was dependent on the SBR‐r content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Ablation properties of zinc borate and aluminum hypophosphite filled silicone rubber composites

The ablative properties of epoxy modified silicone rubber composites filled with zinc borate (ZB) and aluminum hypophosphite (AHP) were studied. The decomposition of the added fillers and covering connection of residual on the substrate contribute to the improvement of heat insulation. The ablation test shows that the formation of a dense char layer with certain strength is key to improving the ablative properties. The optimal ablative performance is achieved when the concentration of ZB and AHP is 10 and 5 phr, respectively. Under such circumstances, the linear ablation rate is as low as 0.032 mm/s, which is about 61% lower than the pure silicone rubber. Furthermore, the structure and composition of the formed char layer were analyzed using X-ray diffraction analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy.     

Coupled analysis on heterogeneous oxidative aging and viscoelastic performance of rubber based on multi-scale simulation

An oxidative aging-viscoelastic constitutive model was established to study the coupled heterogeneous oxidation and viscoelastic performance of rubber during aging process. The basic elasticity and viscoelasticity of rubber materials were comparatively considered as the function of ongoing aging. The dynamic compression process of natural rubber at different aging times was analyzed by the finite element method. And then the effects of oxygen uptake, diffusion, and oxidative reactions on the dynamic viscoelasticity of rubber were analyzed. The permeability of the oxygen in natural rubber was determined by means of molecular dynamics simulation. The results reveal that the heterogeneous degradation caused by diffusion-limited oxidation can lead to a complex stress distribution in the natural rubber specimen under dynamic loading condition; the relaxation time and the energy dissipation of the rubber specimen also increased after aging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47452