Recovery behaviour of shape memory polyurethane based laminates after thermoforming

Abstract

Shape memory polymers (SMPs) can be used to produce a new class of decorative films capable of improved formability and shape recovery in polymer laminates, which are increasingly being used for automotive, aerospace, construction and commercial applications. As a relatively new field there is little knowledge on the shape recovery behaviour of laminates with a SMP film and few methods of quantify that behaviour. The influences of different variables that affect the recovery behaviour of thermoplastic shape memory polyurethanes based laminates including ambient temperature (45 °C and 65 °C), material modulus, and adhesive strength were investigated after thermoforming, through both experimental and modelling methods. The empirical model assisted in identifying the contributions of the adhesive to transfer stresses, which dampened the recovery of the laminate with lower shear strength adhesives. Increasing ambient temperature and the film modulus increased both the final angle recovery ratios and recovery rates.

A self‐healing waterborne poly(urethane‐urea) on reversible covalent interaction for textile breathable coating

“…Waterborne poly(urethane‐urea) (WPU) is attracting significant interest, especially in industrial applications for coating material, 1–3 laminates, 4,5 and artificial leather 6,7 due to their positive impact on safety and sustainability 8 . Using water instead of toxic organic solvents during the coating process of polymers offers the advantage of reducing the negative environmental impact and health concerns when compared with the traditional synthesis processes based on volatile organic compounds (VOCs).…”

Thermo-mechanical transformation of shape memory polymers from initially flat discs to bowls and saddles

“…These materials have been utilized for selffolding and shape changing structures either as multi-layered composites or as monolithic sheets. Self-folding composites comprising a SMP layer and one or more stiff layers can be activated by uniform heating [33][34][35][36][37][38][39] or localized Joule heating [40][41][42][43]. These composites deform along patterns defined by either heating elements or discontinuities in the laminate materials, and have found applications in self-folding robots [42,44] and origami structures [33,40,[45][46][47].…”