Xingyue You,Peng Wang,Yongke Tan,Yujing Li,Jieqiong Wang,Zixuan Li,Yuhui Ao,Ming Li
Second-order nonlinear optical (NLO) materials have become the core of photonic devices. The stability of chromophore arrangement is a key factor limiting the service life of materials. In this study, we employed a novel photo-thermal double-crosslinking networks to enhance the orientation stability of chromophore for the first time by integrating photo and thermal crosslinking techniques. Benzocyclobutene (BCB) and double bonds were introduced as crosslinked units on the polymer and chromophore, respectively. Thermal crosslinking is achieved through the Diels-Alder (D-A) reaction between BCB, while photo crosslinking is accomplished via a thiol-ene click reaction. The UV–vis spectra results demonstrate that photo-thermal double-crosslinking can provide a certain level of protection to the chromophore against decomposition at elevated temperature. Maximum electro-optic coefficient ( r 33 ) of BCB-based double-crosslinking networks is 23.3 p.m. V −1 (at 1.3 μm, 25 wt%). Little difference is observed between the results of photo-thermal double-crosslinking polymer ( r 33 = 5.8 pm V −1 , 10 wt%) and host-guest polymer ( r 33 = 6.7 pm V −1 , 10 wt% ), illustrating that the double-crosslinking reaction does not impair r 33 . The analysis of the thermal simulated depolarization (TSD) curve indicates that the orientation stability of the double-crosslinked network structure (T peak = 162 °C) is significantly enhanced compared to single thermal crosslinking (T peak = 158 °C) or single photo crosslinking (T peak = 144 °C), owing to the dual fixation of the chromophore through both photo and thermal crosslinking processes. It could be concluded that the enhancement of orientation stability does not come at the cost of the electro-optic coefficient. In a word, photo-thermal double-crosslinked second-order nonlinear materials are expected to be a promising option to research NLO optical applications.
Chang-An Xu,Zhuangzhuang Chu,Xingchi Li,Heng Fang,Weijian Zhou,Yang Hu,Xudong Chen,Zhuohong Yang
Epoxy vinyl ester resin is widely used in the field of corrosion protection because of its excellent corrosion resistance and mechanical properties . However, due to the ease of hydrolysis of the ester group in the ester resin, the barrier ability of the coating is reduced, which will accelerate metal corrosion. The existing literature shows that the use of nano-sheet materials such as graphene oxide (GO) can effectively enhance the barrier properties of the coating. In order to solve the poor compatibility and electrical corrosion phenomenon of GO, in this work, renewable vanillin and silicone with excellent anti-corrosive properties were grafted to GO (APGO) by insertion reaction and D-A reaction. Subsequently, a series of new APGO-based epoxy vinyl ester resin composites with excellent mechanical properties and anti-corrosion properties were prepared by thermal crosslinking polymerization. The results showed that when the additive amount of APGO was 0.1 wt%, the comprehensive performance of the composite was the best: the conductivity (1.9 × 10 −13 –5.6 × 10 −13 S/cm) of the composite was far lower than the critical electrical insulation value (10 −9 S/cm), the breaking strength was improved by 38.0 %, the contact angle was increased by 65.7 %, and its anti-corrosion efficiency was up to 99.03 %. After 70 days of immersion in 3.5 wt% salt water, the impedance modulus of the composite at low frequency (Z f = 0.01 Hz) remained 2.23 × 10 10 Ω cm 2 , which was 2 orders of magnitude higher than that of pure epoxy vinyl ester resin (2.43 × 10 8 Ω cm 2 ). The above results were not only related to the maze effect formed by APGO, but also related to the increased crosslinking density of the system. This work provided a novel strategy for preparing GO-based composites with excellent comprehensive properties.
危险品化学品经营许可证（带存储）