Abstract

Hyperbranched polyesters (HBPE) are an important class of hyperbranched polymers having wide range of industrial applications. A novel water soluble HBPE was synthesized from hydroxybutanedioic acid and 2,2,’ 2” nitrilotriethanol by polycondensation method using p-Toluenesulfonic acid (p-TSA) as an acid catalyst. All synthetic procedures were made under a dry nitrogen atmosphere. The chosen molar ratio of 2,2,’ 2” nitrilotriethanol to hydroxybutanedioic acid were 1:3, 1:6, 1:21 for G1,G2 and G5 generations respectively. The resulting products were analysed by 1H NMR, FTIR spectroscopy. An increase in functionality was indicated by end group analysis. The G5 stage HBPE was further reacted with acrylic acid to modify the end groups. The FTIR spectrum indicates the completion of reaction indicating the possibility of using the prepared HBPE as rheology modifier in water based acrylic coatings.

INTRODUCTION

Hyperbranched polymers (HBP) are a new class of polymers having highly branched macromolecules with a large number of reactive end groups. It belongs to a class of three dimensional dendritic structures. HBP are polydisperse and randomly branched with different molecular size and topologies (1-5). They have received wide attention due to their unusual properties such as low viscosity, high reactivity, high degree of branching units, high density of surface functional groups, nano scaled size, low degree of chain entanglement. HBP have been established in many field such as supra molecular chemistry, photochemistry, dye colouration, preparation of nano molecular membranes drug delivery, coating, electrochemistry, curing of epoxy resins, catalysis, pollution management, rheological modification etc. (6-12).
HBPEs are an important class of HBP and are characterized by good thermal, mechanical and chemical properties. HBPE can be synthesised from easily available and inexpensive raw materials have impelled many research groups to investigate HBPEs in details. HBPE of different pseudo generations were synthesized in an acid catalyzed poly ...