Role of Grafting on Particle and Film Morphology and Film Properties of Zero VOC Polyurethane/Poly(meth)acrylate Hybrid Dispersions

Hybrid waterborne dispersions of polyurethane (PU)/poly(meth)acrylic are widely applied in coating and adhesive products, as well as in many other applications. The synergetic performance of the two component polymers is highly dependent on the ability to control the PU and (meth)acrylic network structure. In this work, the effect of grafting and the impact of macromolecular architecture on the particle and film morphology as well as on the properties of PU/(meth)acrylic hybrid films is investigated. It is shown that with grafting, the absolute molar mass distribution (MMD) is shifted toward higher values as the low molar mass PU chains become incorporated in the (meth)acrylic polymer network. Furthermore, by using different types of functional monomers, the nature of the MMD can be altered. Using transmission electron microscopy (TEM) analysis, it is demonstrated that more homogeneous particle and film morphologies are obtained in the case of grafted hybrids. Finally, the impact of network structure on tensile strength is outlined highlighting that grafted polymer films have higher Young's modulus and strain hardening than the non‐grafted ones.