Preparation and properties of poly(urethane acrylate) films for ultraviolet‐curable coatings

Abstract

Four different UV-curable poly(urethane acrylate)s were prepared through the reaction of two diisocyanates [i.e., toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI)] and two polyols [i.e., polycaprolactone triol (PCLT) and polycaprolactone diol (PCLD)], and they were characterized with Fourier transform infrared spectroscopy. The mechanical properties, thermal properties, and water sorption of the cured poly (urethane acrylate)s were also investigated with respect to the chemical structures of the polyols and diisocyanates. In comparison with linear PCLD-TDI and PCLD-IPDI, crosslinked PCLT-TDI and PCLT-IPDI with trifunctional PCLT showed relatively high thermal decomposition temperatures. The hardness and modulus of the UV-cured poly(urethane acrylate) films, which were measured by a nanoindentation technique, were in the following increasing order: PCLD-IPDI $ PCLD-TDI < PCLT-IPDI $ PCLT-TDI. The pencil hardness was 3H for PCLT-IPDI and PCLT-TDI and HB for PCLD-IPDI and PCLD-TDI. Two urethane acrylates prepared from the trifunctional polyol showed better acid and alkali resistances than those made from the bifunctional polyol. These mechanical properties and chemical resistances may have been strongly dependent on the chain flexibility of the molecules and crosslinking density. Regardless of the functionality in the polyol, the change in the yellowness index showed a lower value in the poly(urethane acrylate) coating containing the aliphatic diisocyanate IPDI in comparison with the corresponding poly(urethane acrylate) with the aromatic diisocyanate TDI.

Synthesis and characterization of sequential interpenetrating polymer networks of polyurethane acrylate and polybenzoxazine

“…These observations suggested that urethane acrylate prepolymer had been completely converted to PUA. These IR absorption bands of PUA were in corresponding with the spectra reported by Wang et al [], Çanak and Serhatli [], and Seo et al []. The chemical structure of PUA after UV curing is presented in Scheme .…”

Improving the performance of UV-curable coatings with carbon nanomaterials

“…The low degradation temperature, especially for the HEA-IPDI-HEA, was mainly attributed to fewer stable urethane groups existing in the aliphatic polyurethane acrylates, which could decompose to form alcohol and isocyanate groups. The results obtained here agree with the literature [26,27]. Additionally, with the introduction of additional multi-functional modified CNT and GO, more bifunctional HEA-IPDI-HEA was injected, which led to a decrease in the thermal stability.…”

“…These results indicate that all of the samples in our system presented excellent adhesive performance on the PC substrate and that the limited increase (from 1B to F) of the surface hardness did not lead to the complete hardening of the coating film, which often leads to a decrease in the adhesive performance. The abrasive test is an accurate and repeatable way to determine the abrasion wear characteristics of inks and coatings [27]. The RCA abrasion test presents the combined properties of surface hardness, rigidity and adhesion of the surface coating and is typically used in the 3C (Computer, Communication and Consumer Electronics) industry to the test surface for resistance to abrasion and wear.…”

Synthesis by UV-curing and characterisation of polyurethane acrylate-lithium salts-based polymer electrolytes in lithium batteries

“…It can be seen that a mass loss began at 130 • C for the F4 membrane, due to the partial removal of the alkyl carbonate solution and some solvent remaining. Generally, the first decomposition stage of PUA results from the degradation of urethane segments and the subsequent stage is due to the degradation of soft segments from the polyether or polyester (Gite et al, 2010;Seo et al, 2010). Hence, it is assumed that the second massloss peak corresponds to the urethane bond breakage, which occurs at between 250 • C and 360 • C in this UVcured polymer electrolyte blend.…”