Improved processibility of silicone composites by MQ silicone resins |
| |
| Authors: | Di Huihui Wang Li Zhang Yan Luo Liting Li Houbin Huang Ronghua |
| |
| Affiliation: | 1. School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, People's Republic of China;2. Xi'an Modern Chemistry Research Institute, Xi'an 710065, People's Republic of China;3. National Center for Magnetic Resonance, Wuhan Institute of Physics & Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China;4. School of Printing and Packaging, Wuhan University, Wuhan, Hubei 430072, China |
| |
| Abstract: | Processibilities of silicone composites were always a problem for their high content of SiO2 powders. This article found that the substitution of silicone resins for linear polydimethylsiloxanes (PDMS) made processibilities easier. Three silicone resins (MQ1.0, MQ1.1, and MQ1.2) with clarified chemical structures (by FT IR, 29Si NMR, and GPC) were adopted. Their shearing viscosities [η( )] were greatly higher than PDMS with higher molecular weight, which could be assigned to stronger molecular interactions as surface tension and flowing activation energy ΔE indicated. On the contrary, η( ) of MQ‐PDMS binary blends greatly decreased to that even lower than either components (about 85% utmost decrease comparing to PDMS), for the variation of molecular interaction rather than dilution effect. Furtherly, when PDMS were partly replaced with MQ resins, process time of PDMS–SiO2 silicone composites were greatly shortened (from >6 to 2 h), while with better SiO2 dispersion (Mooney viscosity greatly decreased from 30.0 to 5.0 MU). Better dispersion of SiO2 fillers in composites could be confirmed by SEM and mechanical properties. For the better dispersion, mechanical properties of composites were improved with higher elastic modulus, higher tensile strength, and higher hardness, especially with higher elongation at break (utmost increased from 190% to 277%). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46445. |
| |
| Keywords: | blends mechanical properties rheology synthesis and processing techniques viscosity and viscoelasticity |
|
|
)] were greatly higher than PDMS with higher molecular weight, which could be assigned to stronger molecular interactions as surface tension and flowing activation energy ΔE indicated. On the contrary, η(
) of MQ‐PDMS binary blends greatly decreased to that even lower than either components (about 85% utmost decrease comparing to PDMS), for the variation of molecular interaction rather than dilution effect. Furtherly, when PDMS were partly replaced with MQ resins, process time of PDMS–SiO2 silicone composites were greatly shortened (from >6 to 2 h), while with better SiO2 dispersion (Mooney viscosity greatly decreased from 30.0 to 5.0 MU). Better dispersion of SiO2 fillers in composites could be confirmed by SEM and mechanical properties. For the better dispersion, mechanical properties of composites were improved with higher elastic modulus, higher tensile strength, and higher hardness, especially with higher elongation at break (utmost increased from 190% to 277%). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46445.