Blends of polypropylene with poly(vinyl butyral)

Water Clustering in Polyvinyl Butyral (PVB): Evidenced by Diffusion and Sorption Experiments

Polyvinyl butyral (PVB) is a transparent amorphous polymer often used to protect fragile surfaces such as glass or photovoltaic panels. The polymer is then packaged in the form of adhesive sheets and bonded to the surfaces. The transport and retention of water in PVB are crucial properties to understand as they modulate the polymer's adhesion properties. In this work, we propose a detailed experimental study of water diffusion and sorption in PVB over a wide range of temperatures and humidity levels in the surrounding atmosphere. Using spectroscopic and gravimetric measurements, our study elucidates how the diffusion coefficient varies with temperature or vapor concentration and provides the activation energy for this process. In addition, dynamic vapor sorption experiments reveal (i) a strong dependence of sorption on hydroxyl group (-OH) concentration and (ii) that the solubility of vapor in PVB decreases with temperature. This enables us to trace the heat of the solution of water in PVB. A comparison of the thermodynamic data obtained with those for water in volume and with the engaged species induced clustering model supports the microscopic view of water organization in PVB in the form of clusters induced by hydrogen bonding.

Morphological, dynamic mechanical, rheological and impact strength properties of the PP/PVB blends: the effect of waste PVB as a toughener

In this study, compatibilized PP/PVB blends were prepared and their morphological, dynamic mechanical, rheological and Izod impact strength properties were investigated.

Determining the vinyl alcohol distribution in poly(vinyl butyral) using normal-phase gradient polymer elution chromatography

The vinyl alcohol (VOH) functionality in poly(vinyl butyral) is known to be responsible for a number of important end-use properties, such as controlling adhesion to surfaces, influencing cross-linking behavior, etc. In order to determine the distribution of the VOH percentage in PVB, with the associated averages and polydispersity, we have developed a normal-phase gradient polymer elution chromatography (NP-GPEC) method which relies on both precipitation-redissolution as well as on sorptive interactions between the polymer and the column packing. The method is shown to operate in the linear region of detector response with respect to key operational parameters and is demonstrated to be independent of chemical composition distribution, molar mass, or polydispersity in either molar mass or VOH content. Several examples are given, including where NP-GPEC readily allows visualization of differences between samples that appear identical when analyzed by standard methods.