Study Of Synthesis And Application Of UV Hyperbranched Polymer

Over the past decades, hyperbranched polymers received much attention because of their attractive features such as highly branched, multiple end groups, improved solubility, lower solution viscosity and three-dimensional globular structure. Many synthetic approaches such as self-condensing vinyl polymerization (SCVP), reversible addition-fragmentation chain transfer polymerization (RAFT) and atom transfer radical polymerization (ATRP) have been used to prepare branched polymers. However, many of those methods for synthesis of branched polymers also have significant drawbacks, including the need for complex monomers, time-consuming synthesis procedures and harsh reaction conditions. This paper is divided into two parts, the first part is mainly on the synthesis of branched polymers through the method of mercapto chain-transfer polymerization. Then, the hyperbranched polymers were used in photoresist, and good research results were obtained. The second part is about the synthesis of hyperbranched polyurethane which was used in photoresist, and scanning electron microscope test shows the resolution of this photoresist was 10μm.1) Styrene type of monomer (4-vinyl benzyl thiol) which including both thiol group and double bond was synthesized as branched monomer with chloromethyl styrene and thiourea. A series of hyperbranched polymers with different degree of branching were synthesized through the method of mercapto chain-transfer branched polymerization with styrene (St), acrylic acid (AA), 4-vinyl benzyl thiol and butyl acrylate (BA), and propylene glycol monomethyl acetate (PMA) as the solvent and AIBN as the initiator. The structure of the hyperbranched polymers was characterized by FT IR and ~1H NMR. Molecular weight (Mw), radius of gyration (Rg) and intrinsic viscosity ([η]) were measured by three-detection which including gel permeation chromatography (GPC), laser light scattering (LS), differential viscosity (DV) detectors. The related parameters of Mark-Houwink equation were calculated and the result shows that the hyperbranched polymers were synthesized successfully. The modified hyperbranched polymers were obtained from the modification of the hyperbranched polymers by GMA. A negative-type photoresist based on modified branched polymers was prepared using an optimized composition. The properties and resolution of the negative-type photoresists for the printed circuit board (PCB) were studied. The results show that the prepared photoresist exhibited good behaviors, and the resolution of the circuit based on the negative-type photoresist can reach the level of 40μm.2) UV-curable hyperbranched polyurethane (UV-HBPU) containing carboxyl groups was synthesized from isophorone diisocyanate (IPDI), diethanolamine (DEOA), polyethylene glycol (PEG400), hydroxyethyl acrylate (HEA), and 2,2-bis (hydroxymethyl) propionic acid (DMPA). Fourier-transform infrared spectroscopy (FT IR) and proton nuclear magnetic resonance (~1H NMR) spectroscopy of UV-HBPUs indicated that the synthesis was successful. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the thermal stability of the UV-HBPUs decreased as the HEA content increased. Then, the UV-HBPU was used as a negative-type photoresist for a printed circuit board (PCB). The polymer exhibited excellent photoresist properties, and the resolution of circuits based on this negative-type photoresist reached 10μm.