Water-Assisted Production of Polypropylene/Boehmite Composites

Abstract

In this study polypropylene (PP) matrix-based boehmite alumina (BA) reinforced composites were prepared batchwise in an internal mixer. BA particles up to 10 wt.% were incorporated by 1. traditional melt mixing and 2. in a novel, Water-Assisted (WA) way, called fast evaporation mixing, during which BA was dispersed in PP with the use of an aqueous carrier medium. The WA way with pure water as medium proved to be ineffective because of the presence of the Leidenfrost effect. Therefore, an additional agent, carboxymethyl cellulose (CMC) was used to increase the boiling temperature of the water. Mechanical, morphological and thermal properties of the composites were determined. Scanning electron microscopy images revealed a partially dispersed structure of BA within the PP matrix in all cases, where aggregates and dispersed particles were identified as well. The size of the agglomerates observed was the smallest when BA was incorporated by being dispersed in water/CMC firstly. The mechanical tests results indicated that the reinforcing effect of BA was also most prominent in this case. However, CMC had an opposite effect on PP, than BA thus reducing the overall enhancement in mechanical properties. Differential scanning calorimetry showed an increase in the crystallinity ratio of PP with increasing BA content, which indicates a nucleating effect of BA.

A review of current knowledge and future trends in polymer/boehmite nanocomposites

“…Polypropylene has also been considered as an important matrix for boehmite. [48][49][50] Pedrazzoli 51 studied how boehmite nanoparticles affect the morphology, crystallization, and mechanical properties of the melt processed polypropylene based nanocomposites. The non-modified and benzene sulfonic acid modified boehmite nanoparticles were used as nanofiller.…”

A novel preparation method of polypropylene/natural rubber blends with improved toughness

“…The authors observed that this new technique improves the dispersion of the montmorillonite in the matrix and thereby also increases the mechanical properties of the produced composites. In a later study 30 it was found that the applicability of the technique highly depends on the processing temperature and the water content of the carrier medium. At way too high temperatures (>180°C) and with too high a water concentration of the suspension (solid content <10 wt%), the aqueous slurry is simply not able to make it inside the polymer melt due to the occurrence of the Leidenfrost effect.…”

Development and Analysis of an In-Mold Coating Procedure for Thermoplastic Resin Transfer Molding to Produce PA6 Composites with a Multifunctional Surface

“…In addition to recyclability, sustainability in plastics strategies also includes designing and using polymer products [1,2]. As a result, thermoplastics are becoming more and more important in composite technology [3][4][5][6]. Short-fiber composite products have long been produced by injection molding and extrusion, but the combination of continuous reinforcement structures and thermoplastic matrix materials has only recently become more common.…”