Yuchuan Zhang

Study on crystallization and compatibility of nitrile butadiene rubber (NBR)/polyoxymethlene (POM) blends modified by a polyether polyol

Abstract Blends of nitrile butadiene rubber (NBR) and polyoxymethlene (POM) were prepared by melt mixing, with a polyether polyol (Model KGF400D) used as the compatibilizer. Scanning electron microscopy (SEM) was used to characterize the cryogenically fractured surfaces of the blends clearly, which showed that the compatibility of NBR/POM blends was significantly enhanced with the addition of KGF400D. Both differential scanning calorimetry (DSC) and rubber process analysis (RPA) results clearly indicated the mechanism of compatibility improvement. Dual functions of KGF400D within the NBR/POM blends were found: one was the lubrication effect and the other was the hydrogen bonding between the hydroxyl of KGF400D and ether oxygen group of POM or lone pair electron in the cyano group of NBR.

On Surface Modification of Nano-TiN with Graft Copolymer LMPB-g-KH570

Nano-TiN were modified by the macromolecular coupling agent (LMPB-g-KH570), a graft copolymer of KH570 and LMPB in dimethylbenzene. The graft copolymers molecular structure was confirmed by FTIR and NMR, and its average molecular weight was measured by VPO. The Mn value of LMPB-g-KH570 was calculated as 4025.058, meeting the requirement that optimum number-averaged molecular weight should be in the range of 3000–10000. The graft copolymer LMPB-g-KH570 was used for the surface modification of nano-TiN. The surface properties and thermal stability of modified nano-TiN were investigated by FTIR, TGA, TEM, contact angle, and surface free energy measurement. The results showed that the macromolecular coupling agent bonds covalently onto the surface of nano-TiN particles and forms an organic coating layer. TGA and contact angle measurement indicated that LMPB-g-KH570 molecules were absorbed or anchored on the surface of nano-TiN and its using efficiency is 67.35%, which facilitates to hinder the aggregation of nano-TiN. TEM results also revealed that modified nano-TiN possesses good dispersibility.