Influence of Reactice Processing on the Properties of PP/Glass Fiber Composites Compatibilized with Silane

• Published in: Macromolecular materials and engineering Vol. 291; no. 4; pp. 418 - 427
• Main Authors: Felix, Afonso H. O., Cardozo, Nilo S. M., Nachtigall, Sonia M. B., Mauler, Raquel S.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 07.04.2006; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; compatibilization; Composites; Exact sciences and technology; Forms of application and semi-finished materials; functionalization of polymers; poly(propylene) (PP); Polymer industry, paints, wood; reactive processing; Technology of polymers; Short fiber; In situ; Propylene polymer; Fiber reinforced material; Mechanical properties; compatibilization; Organic silane; reactive processing; Experimental study; Functional polymer; Composite material; Coupling agent; composites; poly(propylene) (PP); Functionalization; Isotactic polymer; Concentration effect; functionalization of polymers; Growth from melt; Glass fiber; Rheological properties
• ISSN: 1438-7492; 1439-2054
• DOI: 10.1002/mame.200500305

Composites of PP reinforced with 20 wt.‐% of short glass fibers were prepared by extrusion using VTES as a coupling agent. The addition of VTES was performed via in‐situ functionalization of PP and by a two‐step process in which PP was functionalized before the composite preparation. The obtained samples were characterized using rheometry, mechanical tests and microscopy. Both processes allowed the fiber/matrix interaction to increase. It was found that the VTES content affected the viscosity of the system by means of three different mechanisms: reduction of β‐scission reactions, decrease of fiber sliding and plasticizing effect on the matrix. Whereas the first two mechanisms increased the viscosity of the final composite after unreacted VTES removal, the third one reduced the viscosity during the process and contributed to fiber‐length preservation. The effects of VTES and peroxide contents on the Young's modulus were closely related to their effects on the final fiber length, indicating the effectiveness of using VTES as a coupling agent. Comparison between in‐situ functionalization and the two‐step process with prefunctionalization showed that in‐situ functionalization led to a lower degree of chain breakage, even when it was performed in the presence of peroxide. Scanning electron micrographs of PP/glass fiber composite prepared without coupling agent.