The researchers then focused on designing better glass fiber reinforced thermal plastics such as polypropylene (PP). Glass fibre reinforced thermoplastics, i.e. PP are one of the most exciting areas in the composites market for both structural and engineering applications. However, glass fibre reinforced thermoplastics often possess poor interfacial adhesion which significantly limits their practical application. The existing traditional coupling agents are facing challenges and limitations of poor interfacial compatibility especially for thermoplastics.
Grafting polymer chains onto the glass fibre (GF) surface holds great promise and could be an effective method to increase the interfacial adhesion of composites based on the mechanism of better interlocking and entanglement with the matrix polymer. The enhanced interfacial adhesion will result in good mechanical properties of the composites.
Along this line, researchers developed a three-step surface modification process to control the interfacial properties of the polymer composites. GF was treated by 3-aminopropyl-triethoxysilane(γ–APS),1, 6-diisocyanatohexane(HDI) and benzylamine, octadecylamine or polyethylene glycol (PEGs) with various chain length stepwise. Researchers grafted organic chain structure onto GF surface. Besides, the surface modified GF was characterized by contact angle measurement, ATR–FTIR and XPS. The results showed that the surface modification method is efficient and successful.
Researchers investigated the effect of the grafting functional groups on the tensile strength of GF/PP composites by tensile test. It is found that the tensile strength of the composites is significantly increased with the lengthening of grafted chain. Thus, modified GF by this method can considerably enhance the tensile strength of PP/GF composites.
These results were published in Engineering Plastics Application, 2015, 43(4), 103-108 and RSC Advances, 2015, 5, 40668–40677.
The work was supported by the One Thousand Talents Program of China, the National Natural Science Foundation of China, etc.
Figure:Three-step surface medication process of glass fibre to control interfacial adhesion for fiber reinforced polymer composites（Image by XTIPC）
Prof. ZHANG Yagang
Xinjiang Technical Institute of Physics & Chemistry