Maleic Anhydride Modified Dicyclopentadiene Resin for Improving Wet Skid Resistance of Silica Filled SSBR/BR Composites  
[PERSON]  
1 School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; [EMAIL_ADDRESS] (R.H.); [EMAIL_ADDRESS] (Z.C. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
1 School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; [EMAIL_ADDRESS] (R.H.); [EMAIL_ADDRESS] (Z.C. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
1 School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; [EMAIL_ADDRESS] (R.H.); [EMAIL_ADDRESS] (Z.C. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
1 School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; [EMAIL_ADDRESS] (R.H.); [EMAIL_ADDRESS] (Z.C. ); [EMAIL_ADDRESS] (K.F.) Footnote 1: email: {yuwen.mdpi.com,liwen.edu,[EMAIL_ADDRESS],[EMAIL_ADDRESS],zhangi.chen@sc  
contact area which divides into penetration area, transition area and traction area between tire and road, resulting from that water film thins under pressure during which elasto-hydrogen lubrication gradually transform to boundary lubrication. As a consequence, propelling the transition from EHL to BL by breaking the thick water film is exactly vital to improve wet friction. Many researchers acknowledge that the reason why silica-filled tire performs better than that with carbon black on wet road is that the silica-water interaction is much stronger than the silica-polymer interaction, making it capable of exposing silica to improve surface roughness and fulfil demand for boundary lubrication [3; 11; 12; 14]. However, silica is easy to aggregate due to its polar surface, which even deteriorates the reinforcement of silica on account of causing the discrepancy of surface energy between silica and rubber chain. As a result, it is desirable to weaken the silica-filler network by adding some additives in order to improve the WSR of silica-filled SSBR/BR compounds. There are two basic requirements for the agents: (1) sufficient compatibility with SSBR; (2) the ability to interact with silica. Many resins contain benzene or other ring structures, such as 2-phenyl-1-propene, phenolic resin, have been thus investigated [15]. However, most petroleum resins are restricted to being antiskid resins due to the primarily rare possibility to modify their nonpolar nature. Differently, dicyclopentadiene (DCPD) resin that is obtained by thermal polymerization and Diels-Alder reaction as shown in Figure 1, can exhibit strong polarity through copolymerizing with some polar monomers [16]. Furthermore, our previous work shows that modified rosin resins greatly improve the WSR of vulcanizates, mainly because of the introduced polar groups [17]. Therefore, we assumed a similarly expectable consequence by modifying DCPD resin and carried out relevant investigation. In this study, the modified DCPD resin was prepared by grafting the reaction of DCPD resin with maleic anhydride. Fourier transform infrared spectrometer (FTIR) and differential scanning calorimetry (DSC) were used to confirm the reaction. Since the effect of MAH content on WSR is associated with both hysteresis and lubrication effect, we not only measured the dynamic properties at low temperature that are acknowledged by most researchers [18; 19; 20; 21], but also innovatively introduced the water contact angle to analyze the interaction between rubber and water, in order to clearly understand how MAH content affects wet friction from the perspective of fluid lubrication. Furthermore, another portable British Pendulum Skid Tester (BPST) was also adopted to evaluate the maximum friction on different substrates, which stimulate real road conditions. Moreover, the effects of M-DCPD on the physical-mechanical properties and cure characteristics were also examined.