Lin Tang, Junliang Zhang and Junwei Gu*. Random copolymer membrane coated PBO fibers with significantly improved interfacial adhesion for PBO fibers/cyanate ester composites. Chinese Journal of Aeronautics, 2021, 34(2): 659-668. 2019IF=2.215.（2區(qū)工程技術(shù)期刊，中國科技期刊卓越行動計劃-領(lǐng)軍期刊類項目）
（https://doi.org/10.1016/j.cja.2020.03.007）
AbstractPoly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers possess excellent dielectric, mechanical properties and heat resistance. However, the surface of PBO fibers is smooth and highly chemical inert, resulting in poor interfacial compatibility to polymer matrix, which severely limits its wider application in high-performance fiber-reinforced resin matrix composites. In this work, random copolymers (P(S-co-BCB-co-MMA)) containing benzocyclobutene in the side-chain were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, which were then utilized to form dense random copolymer membrane on the surface of PBO fibers by thermally cross-linking at 250oC (PBO@P fibers). Four kinds of synthesized P(S-co-BCB-co-MMA) with different number-average molar mass (Mn) were well controlled and possessed narrow dispersity. When the Mn was 32300, the surface roughness of PBO@P fibers was increased from 11 nm (PBO fibers) to 39 nm. In addition, PBO@P fibers presented the optimal interfacial compatibility with bisphenol A cyanate (BADCy) resins. And the single fiber pull-out strength of PBO@P fibers/BADCy micro-composites was 4.5 MPa, increasing by 45.2% in comparison with that of PBO fibers/BADCy micro-composites (3.1 MPa). Meantime, PBO@P fibers still retained excellent tensile strength (about 5.1 GPa). Overall, this work illustrates a simple and efficient surface functionalization method, which would provide a strong theoretical basis and technical support for controlling the surface structure & chemistry of inert substrates.
聚對苯撐苯并二噁唑（PBO）纖維具有優(yōu)異的介電性能、力學(xué)性能和耐熱性能，然而其表面光滑且呈極強的化學(xué)惰性，與樹脂基體相容性極差，嚴(yán)重限制了其在高性能纖維增強樹脂基復(fù)合材料領(lǐng)域更廣的應(yīng)用。本文采用可逆加成-斷裂鏈轉(zhuǎn)移（RAFT）聚合合成一種側(cè)鏈含有苯并環(huán)丁烯的無規(guī)共聚物P(S-co-BCB-co-MMA)，經(jīng)熱交聯(lián)在PBO纖維表面形成一層致密的無規(guī)共聚物膜（PBO@P纖維）。結(jié)果表明，經(jīng)RAFT聚合得到可控的無規(guī)共聚物P(S-co-BCB-co-MMA)具有窄的多分散系數(shù)，且通過熱交聯(lián)（250oC）在PBO纖維表面形成一層無規(guī)共聚物膜。當(dāng)P(S-co-BCB-co-MMA)的分子量（Mn）為32300時，PBO@P纖維的表面粗糙度從11 nm（PBO纖維）提高到39 nm，與雙酚A型氰酸酯（BADCy）樹脂的界面相容性最佳。且PBO@P纖維/BADCy樹脂微復(fù)合材料的單絲拔出強度為4.5 MPa，較PBO纖維/BADCy樹脂微復(fù)合材料的單絲拔出強度（3.1 MPa）提高了45.2%。同時，PBO@P纖維仍保留PBO纖維優(yōu)異的拉伸強度（5.1 GPa）。此外，本文采用簡單、高效的表面改性技術(shù)為調(diào)控惰性基質(zhì)表面結(jié)構(gòu)和表面化學(xué)提供強有力的理論依據(jù)和技術(shù)支撐。
