天然橡胶/再生胶共混胶核磁共振交联密度与共混均匀性的研究

制备了再生胶(RR)不同用量的NR/RR共混胶,并使用核磁共振交联密度仪和RPA对其交联密度与粘弹性进行了研究.结果表明,再生过程中再生胶大分子主链断裂,网络二次重构时不能形成完整的交联网络,两相结构混合不均匀,导致力学性能下降;共混胶中天然橡胶/再生胶橡胶烃比例接近1/1时,共混均匀性最差.其硫化胶力学性能随RR用量的增加先升高后下降.     

胎面再生胶/天然橡胶共混胶性能研究

以胎面再生胶(RU复合胶)为研究对象，通过添加少量天然橡胶(NR)与之共混制备高性能共混胶料。研究了胎面胶再生胶RU 与NR 共混胶的共混比、补强体系、软化体系和防老体系，以及各体系对共混胶的硫化特性、硫化胶的力学性能和耐热老化性能的影响。结果表明，纯胎面胶再生胶RU 具有较好的综合性能。通过与NR 生胶共混，进一步改善了再生胶的加工性能、力学性能和老化性能。对比了多种防老剂对共混胶耐热老化性能的影响，防老剂4010NA以及264的防老效果都较理想。当胎面再生胶中加入20phr的NR生胶,炭黑N220用量为20phr,增塑剂30^#机油为8～12phr,防老剂为1phr 时，共混胶具有较好的力学性能和老化性能，其拉伸强度保持率和拉断伸长率保持率均在90%以上。     

改性白炭黑对NR/ENR共混胶力学性能的影响

研究了沉淀法白炭黑对NR/ENR共混胶力学性能的影响。结果表明,随着未改性白炭黑用量的增加,共混胶力学性能先升高后降低,未改性白炭黑用量为5～10份时共混胶力学性能较好;Si-69,KH-550和间苯二酚六次甲基四胺(PY)对白炭黑都有很好的改性效果,其中Si-69和KH-550用量分别为2.7份时改性效果最佳,PY(间苯二酚和六次甲基四胺用量比为40/60的络合物)用量为1份时改性效果最好。     

甲基丙烯酸缩水甘油酯增强EPDM的力学性能和交联密度

研究了甲基丙烯酸缩水甘油酯(GMA)／三元乙丙橡胶(EPDM)硫化胶的力学性能。结果表明,GMA具有明显的增强效果。GMA对EPDM的增强作用与GMA参与了橡胶的接枝和交联反应有关。     

天然橡胶/杜仲胶并用胶的交联密度与结晶度的关系及其对性能的影响

通过调整硫黄用量,研究天然橡胶(NR)/杜仲胶(EUG)并用胶的交联密度与结晶度的关系及其对并用胶性能的影响。结果表明：NR/EUG并用胶的交联密度与结晶度呈负相关;随着硫黄用量的增大,NR/EUG并用胶的交联密度增大,t₁₀略有缩短,t₉₀变化不大,硬度、耐屈挠性能和抗湿滑性能先提高后降低,滚动阻力和生热下降,储能模量波动减小;当硫黄用量为2～2.5份时,NR/EUG并用胶的交联密度和结晶度较大,物理性能、耐磨性能和抗湿滑性能较好。     

NR/NBR/环氧化天然橡胶共混物的动态力学性能

研究了对叔丁基酚醛树脂用量对NR／NBR／环氧化天然橡胶（ENR）共混物动态力学性能的影响。加对叔丁基酚醛树酯的NR／NBR／ENR共混物有2个动态力学损耗峰（分别对应共混物的玻璃化转变温度Tg1和Tg2）。随着对叔丁基酚醛树脂用量（0－15份）增大,共混物的Tg1基本不变,Tg2则逐渐升高;温度为Tg1的共混物损耗因子（tanδ）峰值化不大,温度为Tg2的共混物tanδ峰值则逐渐增大。通过调节对叔丁基酚醛树脂用量可以改变共混物在0和65℃附近的tanδ值,从而获得抗湿滑性能好、滚动损失小的新型胎面材料。     

炭黑对NBR复合材料交联密度和力学性能的影响

采用核磁共振交联密度仪,考察了炭黑粒径、结构度和用量对丁腈橡胶（NBR）复合材料的交联密度和力学性能的影响规律。研究表明：炭黑加入后硫化胶的交联密度增加,且随炭黑用量增加而增加,随粒径增加而减小;炭黑结构度对化学交联密度影响大于物理交联密度。随着炭黑粒径的减小,硫化胶的拉伸强度、撕裂强度、定伸应力增加,高定伸下炭黑粒径对应力的贡献大于低定伸。炭黑结构度增加,硫化胶的拉伸强度、定伸应力增加,撕裂强度降低。     

热空气老化对丁基橡胶交联密度和力学性能的影响

采用热空气老化试验机研究了丁基橡胶（IIR）的老化行为,获得了不同老化温度和老化时间对IIR交联密度和力学性能的影响规律。结果表明,随着老化时间的延长,IIR硫化胶的交联密度先增大后减小,并随老化温度的升高变化幅度较为明显。拉伸强度、定伸应力和硬度均出现类似变化规律,而拉断伸长率先迅速下降后逐渐趋于平缓。     

不同炭黑补强EPDM/NR再生胶共混胶的性能研究

研究了5种不同粒径和结构的炭黑对EPDM/NR再生胶共混胶物理机械性能的影响.结果表明,随着炭黑粒径的减小和结构度的提高,EPDM/NR再生胶共混胶的物理机械性能提高;炭黑粒径过小时,共混胶物理机械性能有所下降;使用5种炭黑补强时,炭黑N330的补强效果最好.     

CM/CR共混胶硫化体系的研究

研究了7种硫化体系对氯化聚乙烯橡胶（CM）/氯丁橡胶（CR）共混胶力学性能的影响。结果表明,7种硫化体系均能硫化该共混胶,其中复配型硫化剂（TCHC）的硫化胶拉伸强度最大,亚乙基硫脲（NA-22）的硫化胶力学性能较好,噻二唑酯衍生物（TDD）并用硫化体系的硫化时间最短,三巯基均三嗪（TCY）的共混胶门尼粘度高、加工性能差,过氧化物硫化体系的硫化胶力学性能不佳。平衡溶胀法测试结果显示,交联密度与力学性能有一定相关性。     

Influence of phenolic curative on crosslink density and other related properties of dynamically cured NR/HDPE blends

Dynamically cured 60/40 NR/HDPE blends with various amounts of phenolic curative were prepared in an internal mixer at 160°C. A simple blend (i.e., the blend without curative) was also prepared using the same materials and blend proportion for comparison purposes. Mechanical, dynamic, and morphological properties; swelling resistance and crosslink density of the blends were investigated. It was found that the thermoplastic vulcanizates (TPVs) gave superior mechanical and dynamic properties than the simple blend. Furthermore, the mechanical properties in terms of elongation at break, modulus and tensile strength and elastic response in dynamic test in terms of storage modulus increased with increased loading amount of the curative. The complex viscosity also increased but the tan δ and tension set decreased with increased loading level of the curative. The crosslink density of the TPVs was estimated based on the elastic shear modulus. It was found that the crosslink density of the blends increased with increased loading levels of the curative while the degree of swelling decreased. This correlated well with the trend of mechanical and dynamic properties. SEM micrographs were used to confirm the level of mechanical and dynamic properties. It was found that the simple blend at a given blend ratio exhibited co‐continuous phase morphology. However, the TPVs showed micron scale of vulcanized rubber domains dispersed in a continuous HDPE matrix. The size of vulcanized rubber domains decreased with increasing amounts of the curative. This led to greater interfacial adhesion between the phase and hence superior mechanical and dynamic properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

TPI/NR力学性能的分子动力学模拟

为研究杜仲胶(TPI)和天然橡胶(NR)之间的相容性、TPI/NR共混物的力学性能,采用分子动力学(MD)法在Compass力场条件下对其进行了模拟。研究结果表明:通过比较溶度参数差值(Δδ)的大小可预测TPI与NR之间的相容性,TPI/NR属于相容体系;与纯TPI相比,TPI/NR共混物的静态力学性能及动态拉伸抗疲劳性能更加优越。     

锡偶联型溶聚丁苯橡胶/天然橡胶共混物的性能

研究了不同共混比的锡偶联型溶聚丁苯橡胶／天然橡胶（ＳＳＢＲ／ＮＲ）共混物的生胶及硫化胶的性能及断裂形态。实验表明,ＳＳＢＲ／ＮＲ共混物具有单一的玻璃化转变温度、共混体系为相容体系。ＳＳＢＲ与ＮＲ共混后,改善了ＳＳＢＲ的加工性能,提高其拉伸细度和撕裂强度。当ＳＳＢＲ／ＮＲ（质量比）为８０／２０时,共混物的硫化胶具有最优的力学性能。     

NR/CIIR/TPI共混物相容性及力学性能的分子动力学模拟

采用分子动力学(MD)方法计算了不同聚合度的天然橡胶(NR)、氯化丁基橡胶(CIIR)和杜仲胶(TPI)的溶解度参数,分析了体系的相容性;模拟研究了NR/CIIR/TPI共混物的力学性能。结果表明,添加30份以内的TPI可以降低模量,改善共混物的力学性能。     

抗裂口树脂AD-1600对NR/SBR并用胶性能的影响

研究了补强树脂种类及抗裂口树脂AD-1600用量对天然橡胶/丁苯橡胶（NR/SBR）并用胶性能的影响。结果表明,抗裂口树脂AD-1600、补强树脂OD-60均可提高NR/SBR硫化胶的拉伸强度、撕裂强度及耐磨耗性等性能;随AD-1600用量增加,拉伸强度和撕裂强度先增大后减小,DIN磨耗体积先减小后增大,呈单峰型变化规律,但各项性能达到最佳值时AD-1600用量不一致。     

NR/ENR并用胶的性能研究

探讨NR/环氧化天然橡胶（ENR）并用比对NR/ENR并用胶性能的影响。结果表明,NR/ENR并用胶为部分相容体系；并用胶硫化特性和物理性能与NR基本一致,耐热空气老化性能和动态压缩疲劳性能有所下降；当ENR用量较小（10份）时,并用胶抗湿滑性能提高,同时滚动阻力降低。     

稀土掺杂高耐磨炭黑填充型粉末NR研究(Ⅱ)交联密度

以溶胀指数SI（Swelling Index）为指示参数，研究了稀土用量及炭黑用量对稀土掺杂高耐磨炭黑填充型粉末天然橡胶[P（NR／N330-Ln）]硫化胶的交联密度的影响，并与无稀土粉末胶[P（NR／N330）]及无稀土块胶（MNR／N330）的硫化胶做对比。结果表明，随着稀土用量的增加，硫化胶的溶胀指数（SI）的变化出现4个阶段，这是N330粒子上的稀土对硫化胶表现交联密度的贡献有两种相反的作用，即阻碍生成炭黑凝胶从而降低表现交联密度的作用，增大N330-Ln的表面效应，提高稀土结合橡胶的生成量从而提高表现交联密度的作用的综合结果。随着炭黑用量的增加，P（NR／N330）和P（NR／N330-Sm）硫化胶的交联密度高于MNR／N330硫化胶，各种硫化胶在炭黑填充量为100份时的交联密度几乎相同。     

Improved mechanical properties of NR/EPDM blends by controlling the migration of curative and filler via reactive processing technique

Simple blending of natural rubber/ethylene–propylene–diene rubber (NR/EPDM) generally results in inferior mechanical properties because of curative migration and their differences for filler affinity. In this work, the 70/30 and 50/50 NR/EPDM blends prepared by reactive processing techniques were investigated and compared with the simple, nonreactive blends. The reactive blend compounds were prepared by preheating EPDM, containing all curatives to a predetermined time related to their scorch time prior to blending with NR. For the 70/30 gum blends, four types of accelerators were studied: 2,2‐mercaptobenzothiazole (MBT), 2,2‐dithiobis‐ (benzothiazole) (MBTS), N‐cyclohexyl‐2‐benzothiazolesulfenamide (CBS), and N‐tert‐butyl‐2‐benzothiazolesulfenamide (TBBS). When compared with the simple blends, the reactive blends cured with CBS and MBTS showed a clearly improved tensile strength whereas the increase of tensile strength in the blends cured with TBBS and MBT was marginal. However, a dramatic improvement of ultimate tensile properties in the reactive 50/50 NR/EPDM blends cured with TBBS was observed when compared with the simple blend. For the N‐550‐filled blends at the blend ratios of 70/30 and 50/50, the reactive‐filled blends prepared under the optimized preheating times demonstrated superior tensile strength and elongation at break over the simple blends. The improved crosslink and/or filler distribution between the two rubber phases in the reactive blends accounts for such improvement in their mechanical properties. This is shown in the scanning electron micrographs of the tensile fractured surfaces of the reactive blends, which indicate a more homogeneous blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

CR/NR共混物的物理性能和电性能评价

研究了CR和NR共混纯胶和炭黑填充胶的共硫化。共混硫化胶的硫化特性和物理性能都有明显改善。进行了介电性能测量,并研究了介电性能随共混组分变化与共混物力学性能的关系。用SEM来确定共混硫化胶的形态学变化,以说明观察到的物理性能改进的原因。     

NR/BR/NBR并用胶的结构与性能

研究了NR／BR／NBR并用胶的结构与性能。透射电子显微镜分析显示，随着NBR用量的增大，炭黑的分散趋于均匀；NR／BR／NBR并用胶出现两个玻璃化温度，在O℃时的tanδ值增幅较大，而在65和80℃时的tanδ值变化不大；并用胶物理性能变化不大。通过调节NBR用量可获得抗湿滑性能较好、滚动阻力和生热小的胎面胶。