How the Aggregates Determine Bound Rubber Models in Silicone Rubber? A Contrast Matching Neutron Scattering Study  

作　　者：Li-Zhao Huang Yue Shui Wei Chen Zhong-Ming Li Hong-Tao Song Guang-Ai Sun Jia-Zhuang Xu Gan-Ji Zhong Dong Liu 

机构地区：[1]Key Laboratory of Neutron Physics and Institute of Nucear Physics and Chemistry(NPC),China Academy of Engineeing Physict(CAEP),Mcnyang 621999,China [2]National Synchrotron Radiation Lab,CAS Key Laboratory of soft Mtter Chemisty Anhui Provincial fngineing Laboratory of Advanced funcionad Poymer Film,University of Science and Technology of China,Hefei 230026,China [3]College of Polymer cience and Engineering,state Key Laboratory of Polymer Materials Engineering Sichuan University,Chengdu 61065,China

出　　处：《Chinese Journal of Polymer Science》2021年第3期365-376,I0007,共13页高分子科学（英文版）

基　　金：financially supported by the National Key R&D Program of China (No. 2018YFB0704200);the National Natural Science Foundation of China (Nos. 11605171 and 11705173);the Foundation of President of CAEP (No. YZJJLX2018004)。

摘　　要：The correlation between aggregates and bound rubber structures in silicone rubbers(S(phr)) with various silica fractions(ΦSi) has been investigated by contrast matching small-angle neutron scattering(SANS), swelling kinetics, and low-field nuclear magnetic resonance(NMR).Mixed solvents with deuterated cyclohexane fractions of 4.9% and 53.7% were chosen to match the scattering length densities of the matrix(SMP(phr)) and the filler(SMS(phr)), respectively. All the data consistently suggest that:(i) There is a critical threshold ΦSic between 10 and 30 phr;below ΦSic, the isolated aggregates are dominant, while beyond ΦSic, some rubber fraction is trapped among the agglomerate;(ii) ΦSiindependent thicknesses around 7.5 nm(NMR) and 8.6 nm(SANS) suggest that the bound rubber formation is determined by inherent properties of the components, and the power-law around 4.2 suggests an exponential changed gradient density of the bound rubber;(iii) SMS(80) presents a bicontinuous bound rubber with three characteristic lengths of 41, 100, and 234 nm. The expanded correlation length, a 20 nm smaller aggregate sizes suggest that such existent bicontinuous network in dry samples with less ΦSi is kind of impacted by swelling. With the obtained bound rubber models, the reinforcing mechanism of filled silicone rubber is elucidated.

关 键 词：Silicone rubber Bound rubber structures Small-angle neutron scattering(SANS) Nuclear magnetic resonance(NMR) 

分 类 号：TQ333.93[化学工程—橡胶工业]