Preparation and properties of crosslinkable waterborne polyurethanes containing aminoplast(I)

Abstract

A series of crosslinkable, waterborne polyurethanes (I-WBPUs) were prepared by in-situ polymerization using isophorone diisocyanate (IPDI)/poly(tetramethylene oxide) glycol (PTMG, M n =2,000)/ dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA)/aminoplast [hexakis(methoxymethyl)melamine (HMMM)] as a crosslinking agent. Typical crosslinkable, waterborne polyurethanes (B-WBPUs) blended from WBPU dispersion and aqueous HMMM solution was also prepared to compare with the I-WBPUs. The crosslinking reaction between WBPU and HMMM was verified using FTIR and XPS analysis. The effect of the HMMM contents on the dynamic mechanical thermal, thermal, mechanical, and adhesion properties of the I-WBPU and B-WBPU films were investigated. The storage modulus (E'), glass transition temperatures of the soft segment (T gs ) and the amorphous regions of higher order (T gh ), melting temperature (T m ), integral procedural decomposition temperature (IPDT), residual weight, T 10% and T 50% (the temperature where 10 and 50% weight loss occurred), tensile strength, initial modulus, hardness, and adhesive strength of both I-WBPU and B-WBPU systems increased with increasing HMMM content. However, these properties of the I-WBPU system were higher than those of the B-WBPU system at the same HMMM content. These results confirmed the in-situ polymerization used in this study to be a more effective method to improve the properties of the WBPU materials compared to the simple blending process.

Synthesis and characterization of novel polyurethanes based on 4-{(4-hydroxyphenyl)iminomethyl}phenol

“…In literature, many types of PUs based on a number of diols and diisocyanates have been prepared and studied for various applications. [3][4][5][6][7][8][9][10] The hard segments can also be based on polyester 11 or polyamide. 12 At ambient temperatures, the hard segments are incompatible with the soft segments.…”

Properties of crosslinked waterborne polyurethane adhesives with modified melamine: Effect of curing time, temperature, and HMMM content

“…We observed that the viscosity of the dispersions increases with increasing HMMM content. This increase in viscosity might be due to stiff polyurethane chains in the crosslinked structure [17]. The viscosity of HMMM-crosslinked WBPU with excess HMMM content was lower than that of the observed optimum HMMMcrosslinked WBPU dispersion.…”

Preparation and properties of waterborne polyurethane-silane: A promising antifouling coating

“…To improve these properties, significant efforts have been made during the last decade with various approaches such as using a higher 2,2-dimethylol propionic acid (DMPA) content, using poly(tetramethylene adipate glycol), incorporating an aliphatic hardener, blending and crosslinking. [1][2][3] Recently the thermal and mechanical properties were improved by making various WBPUnanocomposites. 4 Recent years have seen a rapid upsurge of silane technology in the field of corrosion and antifouling coatings.…”