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Multigenerational Hyperbranched Waterborne Polyurethane Synthesis and Characterization of Structure and Properties

Author: LiuYuHang
Tutor: SunNing
School: Wuyi University
Course: Applied Chemistry
Keywords: hyperbranched polyurethane generation waterborne structure property
CLC: O631.3
Type: Master's thesis
Year: 2011
Downloads: 59
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Abstract

Hyperbranched polymer is one of the hot research spots of the polymer material research fields in recent years. Due to its special structure and unique physical and chemical characteristics, hyperbranched polymer has attracted much attention. In this decade, the research area of hyperbranched polymer has developed from synthesis and the research of the chemical and physical properties to the molecular theory research, various functionalizations and also the preliminarily researches of the application. Hyperbranched polyurethane (HPU) material, having both the unique structural characteristics of hyperbranched polymer and the excellent properties of the polyurethane, has fixed much attention from the polymer materials scientists. However, the comprehensive studies of the different generation products of the HPU haven’t been reported. The study in the different generation HPU is not only an innovative research work, but also has the important academic value and the potential value of the practical application.This study using the simple and convenient monomers successfully prepared the different generation HPU products via the couple monomer reaction method and the NCO measurement. And then a series of the characterizations and tests were carried out on the products, respectively to study the relationships between the structure and performance.The major work includes the following two aspects:1. the synthesis research of the different generation HPUThis experiment using toluene-2,4-diisocyanate (TDI), dimethylolpropionic acid (DMPA) and diethanolamine (DEOA) as the main reaction monomers, through the A2+ B2B* method synthesized AB2-type intermediate, and then polymerized to obtain the hyperbranched structure. The whole reaction course was monitored by the NCO value measured by the dibutylamine method. And using dibutylamine (DBA) as the terminator, the reaction was terminated when the measured NCO value and the theoretical NCO value was matched. Finally, the different generation HPU products were synthesized and the yield was up to 90%.All the products characterized by the FT-IR and NMR spectroscopy. And the results showed the hyperbranched structure was created. And the degrees of branched was also calculated. At the same time, the molecular weight of all the HPU products have measured by using the GPC with RI detector and viscosity detector and the results showed that each generation products was within the scope of the calculated theoretical molecular weight. In conclusion, the different generation HPU products synthesized successfully.2. the study in the structure and properties of the different generation HPUFirst, the Ubbelohde and the GPC with viscometer were used to investigate the rheologicbehaviour of the different generation HPU. And then the thermal properties were studied by the FTIR, TG, DSC and TG-FTIR compared with the liner polyurethane (LPU).The viscosities of the later reaction system were measured by the Ubbelohde. And the intrinsic viscosities of the HPU products were also measured by the GPC with viscosity detector. It found that with the reaction time increasing the system viscosity rose up. But between the 3 and 4 generation products the viscosities declined for a short time which could not explained by the traditional polymer theory. And the above results showed that the different generation HPU has different rotation radiuses and with the generation increasing the rotation radius has a period of decline.Compared the HPU products with the LPU which has similar chemical composition, the thermal properties were obvious different and the increased generation barely affected the thermal properties in the HPU structures. While the glass transition temperature (Tg) results showed that the Tg of the hyperbranched structure were significantly higher than the linear structure’s. And with the increase of generation, the Tg increased.At last the HPU products and LPU were mixed at a certain ratio respectively to study the performance of the coating films. The results showed that the gloss and the hardness increased obviously by the mixing of the hyperbranched structure, while the flexibility and the impact resistance declined.

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