Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Effects of water immersion‐freeze‐thaw cycling on the properties of wood‐polypropylene composites containing pigments

Effects of water immersion‐freeze‐thaw cycling on the properties of wood‐polypropylene composites... Purpose – The purpose of this paper is to study the effects of water immersion‐freeze‐thaw treatment on the physical properties, flexural strength (FS) and morphology of wood‐polypropylene composites containing pigments. Design/methodology/approach – Wood‐polypropylene composites containing brown, green and grey pigments were compounded in a conical twin‐screw extruder. A composite manufactured without any pigment addition was used as a reference. The amount of pelletized wood, polypropylene and coupling agent (MAPP) was kept constant. The moisture content, thickness swelling (TS), FS and surface colour of the composites were measured before and after water immersion‐freeze‐thaw cycling. Scanning electron microscopy (SEM) was used to study the morphology of the composites. Findings – FS and dimensional stability were reduced after exposure to water immersion‐freeze‐thaw cycling for all composites. The surface properties (colour and roughness) of the composites also changed after exposure to water immersion‐freeze‐thaw cycling. The degree of change depended on the presence of pigment and the type of polypropylene (neat or recycled), however. Research limitations/implications – This study is a part of an ongoing study on weathering of wood‐polymer composites (WPC) containing different additives. The results of this study were obtained from accelerated laboratory experiments. Practical implications – Inorganic pigments are widely used as additives in plastics, because they have an excellent UV absorption, good IR‐reflective properties and heat stability. The research revealed that metal‐containing pigments had an effect on degradation in quality of wood‐polypropylene composites exposed to water immersion‐freeze‐thaw cyclic treatment. The addition of metal‐containing pigments to composite formulation resulted in a higher susceptibility of wood‐polypropylene composites to water absorption, and as a consequence to a higher drop of FS compared to composites made without pigment. The polymer matrix plays an important role in the protection of WPC against weathering. Originality/value – This paper will help in understanding possible problems in the durability of wood‐polypropylene composites compounded with metal‐based pigments when they are exposed to water immersion‐freeze‐thaw cyclic treatment. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Pigment & Resin Technology Emerald Publishing

Effects of water immersion‐freeze‐thaw cycling on the properties of wood‐polypropylene composites containing pigments

Download PDF
7 pages

Loading next page...
 
/lp/emerald-publishing/effects-of-water-immersion-freeze-thaw-cycling-on-the-properties-of-YqtU6nxAnz
Publisher
Emerald Publishing
Copyright
Copyright © 2011 Emerald Group Publishing Limited. All rights reserved.
ISSN
0369-9420
DOI
10.1108/03699421111180536
Publisher site
See Article on Publisher Site

Abstract

Purpose – The purpose of this paper is to study the effects of water immersion‐freeze‐thaw treatment on the physical properties, flexural strength (FS) and morphology of wood‐polypropylene composites containing pigments. Design/methodology/approach – Wood‐polypropylene composites containing brown, green and grey pigments were compounded in a conical twin‐screw extruder. A composite manufactured without any pigment addition was used as a reference. The amount of pelletized wood, polypropylene and coupling agent (MAPP) was kept constant. The moisture content, thickness swelling (TS), FS and surface colour of the composites were measured before and after water immersion‐freeze‐thaw cycling. Scanning electron microscopy (SEM) was used to study the morphology of the composites. Findings – FS and dimensional stability were reduced after exposure to water immersion‐freeze‐thaw cycling for all composites. The surface properties (colour and roughness) of the composites also changed after exposure to water immersion‐freeze‐thaw cycling. The degree of change depended on the presence of pigment and the type of polypropylene (neat or recycled), however. Research limitations/implications – This study is a part of an ongoing study on weathering of wood‐polymer composites (WPC) containing different additives. The results of this study were obtained from accelerated laboratory experiments. Practical implications – Inorganic pigments are widely used as additives in plastics, because they have an excellent UV absorption, good IR‐reflective properties and heat stability. The research revealed that metal‐containing pigments had an effect on degradation in quality of wood‐polypropylene composites exposed to water immersion‐freeze‐thaw cyclic treatment. The addition of metal‐containing pigments to composite formulation resulted in a higher susceptibility of wood‐polypropylene composites to water absorption, and as a consequence to a higher drop of FS compared to composites made without pigment. The polymer matrix plays an important role in the protection of WPC against weathering. Originality/value – This paper will help in understanding possible problems in the durability of wood‐polypropylene composites compounded with metal‐based pigments when they are exposed to water immersion‐freeze‐thaw cyclic treatment.

Journal

Pigment & Resin Technology – Emerald Publishing

Published: Nov 8, 2011

Keywords: Physical properties of materials; Pigments; Wood‐polymer composites; Residual flexural strength; Colour change; Polypropylene; Thickness swelling

References

  • Dimensional stability and mechanical behaviour of wood‐plastic composites based on recycled and virgin high‐density polyethylene (HDPE)
    Adhikary, K.B.; Pang, S.; Staiger, M.P.
  • Mechanical performance of Kraft fibre reinforced polypropylene composites: influence of fibre length, fibre beating and hydrothermal ageing
    Beg, M.D.H.; Pickering, K.L.
  • Durability and mechanical properties of silane cross‐linked wood thermoplastic composites
    Bengtsson, M.; Stark, N.M.; Oksman, K.
  • Effect of processing method and moisture history on laboratory fungal resistance of wood‐HDPE composite
    Clemons, C.M.; Ibach, R.E.
  • Comparison of water absorption in natural cellulosic fibers from wood and one‐year crops in polypropylene composites and its influence on their mechanical properties
    Espert, A.; Vilaplana, F.; Karlsson, S.
  • Wood plastic composites weathering: visual appearance and chemical changes
    Fabiyi, J.S.; McDonald, A.G.; Wolcott, M.P.; Griffiths, P.R.
  • Colour and discoloration
    Hon, D.N.‐S.; Minemura, N.
  • Environmental effects on the degradation behaviour of sisal fibre reinforced polypropylene composites
    Joseph, P.V.; Rabello, M.S.; Mattoso, L.H.C.; Joseph, K.; Thomas, S.
  • Surface deterioration of wood‐flour polypropylene composites by weathering trials
    Kiguchi, M.; Kataoka, Y.; Matsunaga, H.; Yamamoto, K.; Evans, P.D.
  • Wood‐plastic Composites
    Klyosov, A.
  • Accelerated weathering of polypropylene/wood flour composites
    La Mantia, F.P.; Morreale, M.
  • Durability of wood polymer composites: part1. Influence of wood on the photochemical properties
    Ndiaye, D.; Fanton, E.; Morlat‐Therias, S.; Vidal, L.; Tidjani, A.; Gardette, J.‐L.
  • Durability of wood flour‐plastic composites exposed to accelerated freeze‐thaw cycling. II. High density polyethylene matrix
    Pilarski, J.M.; Matuana, L.M.
  • Interface modification and mechanical properties of natural fiber‐polyolefin composite products
    Sain, S.; Suhara, P.; Law, S.; Bouilloux, A.
  • UV aging of PP/wood‐fibre composites
    Seldén, R.; Nyström, B.; Långström, R.
  • Effect of weathering cycle and manufacturing method on performance of wood flour and high‐density polyethylene composites
    Stark, N.M.
  • Effect of processing method on surface and weathering characteristics of wood‐flour/HDPE composites
    Stark, N.M.; Matuana, L.M.; Clemons, G.M.
  • Hydrothermal weathering of rice hull /HDPE composites under extreme climatic conditions
    Wang, W.; Sain, M.; Cooper, P.A.