Pretreatment Of QF With Terminalalkynes-containg Silane Coupling Agent And Properties Of Their PSA Composites For Wave-transmitting Applications

Quartz fiber (QF) reinforced Silicon-containing Arylacetylene resin (PSA) composite was a novel heat-resistance wave-transmitting material, and had an application prospect. PSA which had stiff structure in chain, weak molecular polarity and toughness had unmatched interface combined with QF.A new silane coupling agent containing terminal alkyne and benzene ring (AG-2) was designed and employed to modify the interface of QF/PSA, and the influence of the coupling agent on mechanical properties of composite were researched to judge the performance.AG-2was synthesized by reacting (4-Bromophenylethynyl) trimethylsilane and Trimethoxy chloro silane and temperature of reaction system, deprotection reagent and time were studied to optimize to synthesis. Fourier transform infrared spectroscopy(FT-IR) and Nuclear magnetic resonance(1H-NMR) were used to characterize the novel silane’s structures. Under the optimal treatment conditions, the results showed that the interlaminar shear strength(ILSS) of the treated QF/PSA composite had been tremendously improved by more than35%compared with untreated. The factors that influenced the modified effects of AG-2were studied. The optimal treating process for quartz fiber was as follows:1.5-2.0wt%fresh coupling agent was dissolved in dehydrated THF and impregnated QF under sealing environment was for1.Oh. The mechanisms between fiber and composite were studied by a variety of analysis methods such asThermal Gravity Analysis (TGA)、Dynamic Stability Control(DSC)、X-ray Photoeletron Spectroscopy(XPS)、Atom Force Microscope(AFM)、Scanning Electron Microscope(SEM)、FT-IR and contact angle analysis. It revealed that the coupling agent reacted with the active groups on fiber surface and non-polar functional group was introduced during this process, which increased QF’s surface energy andimproved wettability as well as mechanical reaction. The AG-2also had alkynyl groups which could crosslink with PSA during hot-mold compression moulding. As the result, the fiber and the resin were connected through a bridge of AG-2and strengthened the interfacial adhesion performance. Also the heat-resistance of AG-2was studied and figured out the residual rate was80%at200℃.Themechanical behavior including ILSS and flexural properties under200℃was examined. The results showed that ILSS was increased by33%compared with untreated, but went down by6%compared with room temperature’s; flexural strength was increased by35%compared with untreated, but went down by8%compared with room temperature’s;while the flexural module didn’t change a lot.SEM was used to research the difference of fracture morphology between room temperature and250℃, and figured out the interfacial adhesion of composite was decreased under250℃. Added AG-2could restore the interfacial adhesion but worse than room temperature’s.