Xie Hong-quan

Development of a Hybrid Photopolymer for Stereolithography

New liquid free radical-cationic hybrid photopolymer, consisting of acrylate-based photocurable resin and epoxy-based photosensitive resin for stereolithography by UV laser was developed. The experiment results indicated that the hybrid photopolymer exhibits advantages of both the acrylate-based photosensitive resin and the epoxy-based photosensitive polymer contained in the hybrid system with relatively high photospeed and low linear shrinkage. Stereolithography parts without obvious distortion were built on the stereolithography apparatus HRPLA-I from this hybrid resin successfully and efficiently.

COLOR TUNABLE LIGHT-EMITTING DIODES BASED ON POLYMER/INORGANIC HETEROJUNCTION

By using p-type polymer poly(2,5-Didodecyloxy-1,4-Phenylenylenevinylene) (PDDOPV) and n-type inorganic material ZnO:Zn, the electronluminescent (EL) emission from bilayer device based on polymer/inorganic heterojunction was successfully demonstrated. In comparison with single layer polymer device, with dc voltage of 10V, the brightness and luminous efficiency of bilayer device were enhanced 14 and 26 times, respectively. The EL spectrum of bilayer device is not identical to the characteristic emission spectrum of either PDDOPV or ZnO:Zn, and shifts continuously towards to short wavelength direction as the applied voltage increases.

Complexation between borate ion and hydroxyl groups of phenol-formaldehyde resol resin

The complexation reaction between borate ions and phenol-formaldehyde resol resin in aqueous solution was studied by pH measurement, small model molecules and infrared spectroscopy. The results show that the complexation can proceed completely and rapidly at room temperature. Borate ion attacks phenol hydroxyl groups and adjacent position hydroxymethyl groups on the phenol ring of the resin, and forms the coordinate bond between boron atom in borate ion and oxygen atom in the hydroxyl groups. The complexation is a quantitative reaction. The complex is a six member ring containing two oxygens and one boron. The complexation can release hydrogen ions resulting in the decreasing pH in the resin solution.