Effect of compatibiliser on rheological behaviour of straw fibre/low density polyethylene composites

Abstract

Rheological behaviour of suspensions of straw fibre in low density polyethylene (LDPE) melts was investigated at a certain temperature over a wide range of frequencies using a plate rheometer operated in dynamic mode. The viscoelastic of composite melt changed gradually with the straw fibre content increasing, for example at the low frequency region the slope of the G′ decreased from 1.67 of the plain LDPE to 0.889 of 50 wt-% straw fibre plastic composite. The addition of compatibiliser doubled the tensile strength, and the relaxation time reduced from 405 to 214 s. It was observed that the presence of compatibiliser may be attributed to improve interaction between the polymer and filler, which reduces the resistance of the agglomeration of straw fibres, lessening the relaxation time. Consequently, the straw fibre plastic composite is easier to produce.

Keywords

Straw fibre polymer composite Rheological behaviour Relaxation time Compatibiliser

Get full access to this article

View all access options for this article.

References

Shibata

, Cao

and Fukumoto

: ‘Press forming of short natural fiber-reinforced biodegradable resin: Effects of fiber volume and length on flexural properties’, Polym. Test., 2005, 24, (8), 1005–1011.

Kim

S. J.

, Moon

J. B.

, Kim

G. H.

, et al., ‘Mechanical properties of polypropylene/natural fiber composites: comparison of wood fiber and cotton fiber’, Polym. Test., 2008, 27, (7), 801–806.

Marcovich

N. E.

, Reboredo

M. M.

, Kenny

, et al., ‘Rheology of particle suspensions in viscoelastic media. Wood flour-polypropylene melt’, Rheol. Acta, 2004, 43, (3), 293–303.

Zhang

S. Y.

, Zhang

, Bousmina

, et al., ‘Effects of raw fiber materials, fiber content, and coupling agent content on selected properties of polyethylene/wood fiber composites’, Polym. Eng. Sci., 2007, 47, (10), 1678–1687.

Harper

and Wolcott

: ‘Interaction between coupling agent and lubricants in wood-polypropylene composites’, Composites A, 2004, 35A, (3), 385–394.

Solomon

M. J.

and Lu

: ‘Rheology and dynamics of particles in viscoelastic media’, Curr. Opin. Colloid Interface Sci., 2001, 6, (5), 430–437.

Chaouche

and Koch

D. L.

: ‘Rheology of non-Brownian rigid fiber suspensions with adhesive contacts’, J. Rheol., 2001, 45, (2), 369–382.

Tian

, Yu

and Zhou

: ‘The preparation and rheology characterization of long chain branching polypropylene’, Polymers, 2006, 47, (23), 7962–7969.

Hristov

and Vasileva

: ‘Dynamic mechanical and thermal properties of modified poly (propylene) wood fiber composites’, Macromol. Mater. Eng., 2003, 288, (10), 798–806.

10.

Azizi

and Ghasemi

: ‘Investigation on the dynamic melt rheological properties of polypropylene/wood flour composites’, Polym. Compos., 2009, 30, (4), 429–435.

11.

Oksman

and Lindberg

: ‘Influence of thermoplastic elastomers on adhesion in polyethylene-wood flour composites’, J. Appl. Polym. Sci., 1998, 68, (11), 1845–1855.

12.

Aguilar

, Vega

J. F.

, Sanz

, et al., ‘New aspects on the rheological behaviour of metallocene catalysed polyethylenes’, Polymers, 2001, 42, (24), 9713–9721.

13.

Friedrich

and Braun

: ‘Generalized Cole-Cole behavior and its rheological relevance’, Rheol. Acta, 1992, 31, (4), 309–322.

14.

Zheng

, Cao

Y. X.

and Du

: ‘Dynamic rheological behavior of polypropylene filled with ultra-fine powdered rubber particles’, Chin. J. Polym. Sci., 2004, 22, (4), 363–367.

15.

Zheng

, Zhang

X. W.

, Pan

, et al., ‘Polystyrene/Sn-Pb alloy blends. I. Dynamic rheological behavior’, J. Appl. Polym. Sci., 2002, 86, (12), 3166–3172.

16.

Roths

, Marth

, Weese

, et al., ‘A generalized regularization method for nonlinear ill-posed problems enhanced for nonlinear regularization terms’, Comput. Phys. Commun., 2001, 139, (3), 279–296.