Effect of NCO/OH ratio on the physico-mechanical properties of polyurethane-polyurea hybrid spray coatings

El‐Sayed Negim, K. Omurbekova, Lyazzat Bekbayeva, Abdasssalam Abdelhafiz

2020

Data confidence 70 medium

How this score is calculated

It is built from checkable properties of the record itself: whether the article has a DOI, how many independent sources confirmed its data, whether the required fields are filled in, and how recent the latest confirmation is. Disagreement between sources and a missing identifier lower it. A value of 80 or above means the record was published without further checking; 60 to 79 means it is published at reduced confidence, with a manual check advisable. A record verified by an editor by hand is never pushed below 90 by a recalculation. This scores our data about the article, not the article itself.

Abstract

Polyurethane- polyurea hybrid spray coating was prepared by two steps polymerization. In the first step, polyurethane prepolymers (PUs) were prepared by polyaddition reaction based on 4,4-methylene diphebyl dissocyanate (4,4 MDI), poly(oxytetramethylene) glycol (PTMG), polyoxypropylene glycol (PPG), and triol (trade name FA-703) with different NCO/OH molar ratios. IR spectroscopy and acid-base titration were used to check the NCO content of the prepolymers. In the second step, polyurethane-polyurea hybrid resin was prepared by mixing the polyurethane prepolymer (PU) with polyoxypropylenediamine (POPA) at constant molar ratio (1: 1). The effect of NCO/OH ratios on physico-mechanical properties of the polyurethane-polyurea hybrid coating films was studied including viscosity, tensile strength, elongation at break, tear strength, contact angle and adhesion. The results obtained showed that tensile strength, contact angle and hardness increased, while viscosity, elongation, adhesion and tear strength decreased with increasing NCO/OH molar ratio.