Polystyrene sisal

The chemical treatments such as benzoylation, polystyrene maleic anhydride (PSMA) coating and acetylation of short sisal fibers have been found effective in improving fiber matrix adhesion of polystyrene/sisal composites. It has been reported that the... 

Nair, K.C.M. and Thomas, S. (2003) Effect of interface modification on the mechanical properties of polystyrene-sisal fiber composites. Polym. Compos., 24, 332-343. 

Nair KCB, Thomas S. 2003. Effect of Interface Modification on the Mechanical Properties of Polystyrene-Sisal Fiber Composites. Polym Composite 24(3) 332-343. 

U.S. Pat. No. 6,255,368 [114] describes plastic cellulosic composite pellets comprising 20-60% by weight of polyethylene, polypropylene or polystyrene, 40-80% of cellulosic fiber (jute, kenaf, sisal, bamboo, rice hulls, corn husks, wood fiber, and wood flour) with an aspect ratio of between 2 and 20 and a trace of mineral coating (talc) dispersed on the surface of the pellet. 

Natural fibers can be classified as seed fibers (such as cotton), bast fibers (like flax, hemp, jute, kenaf, ramie), hard fibers (like sisal), fi-uit fibers (like coir), and wood fibers. The chemical composition and dimensions of some common agro-fibers are presented in Table 5.21. The origin of wood fibers can be sawmill chips, sawdust, wood flour or powder, cutter shavings, pulp or wood residues. As binders for these fibers, both thermosetting (like phenolic, epoxy, polyester) resins and thermosetting matrices [such as polyethylene (LDPE, HDPE), polypropylene (PP), poly(vinyl chloride) (PVC), polystyrene (PS)j can be used. Thermoplastic composites are, however, less expensive to process than thermosetting composites, in addition to their ability to be manufactured into complex shapes. 

Tserki V et al (2(X)5) A study of the effect of acetylation and propionylation surface treatments on natural fibres. Compos A Appl Sci Manuf 36(8) 1110-1118 Nair KCM, Thomas S, Groeninckx G (2001) Thermal and dynamic mechanical analysis of polystyrene composites reinforced with short sisal fibres. Compos Sci Technol 61(16) 2519-2529... 

Finally, a possible method for estimation of IFSS in lignocellulosic fiber composites could be based on the evaluation of the critical length 4 at the condition of maximized mechanical properties [55,56]. According to Nair et al. [56], as the fiber length increases, there is a chance for better orientation that may lead to an improvement in mechanical properties of the composites. Based on this assumption, critical lengths of 6 mm for sisal fibers in polyethylene [55] and 10 mm for sisal fibers in polystyrene composites were reported [56]. Even though the authors have not attempted to calculate the IFSS, these reported critical length values are comparable to those obtained for sisal fibers in polyester matrix [51, 57]. As earlier mentioned in this chapter, with the value of the IFSS could then be calculated by means of Equation (9.6). 

Nair KCM, Diwan SM, Thomas S et al (1996) Tensile properties of short sisal fiber-reinforced polystyrene composites. J Appl Polym Sci 60 1483-1497... 

The matrices used in sisal fiber-reinforced composites include thermoplastics (polyethylene, polypropylene, polystyrene, PVC, etc.), thermosets (epoxy, polyester, and phenol-formaldehyde resin, etc.), rubber (namral rubber, styrene-buta-diene mbber, etc.) gypsum, and cement. The effects of fiber length, fiber orientation, processing methods, fiber volume fi-action and fiber surface treatment on the mechanical and physical properties of sisal fiber reinforced composites have been smdied. 

Testing of mechanical properties such as tensile strength (ASTM-D-638), flexural strength (ASTM-D-790), and impact strength (ASTM-D-256) was done following standard methods. The water absorption of both untreated and treated composites was determined as per ASTM-D-570. The variation in tensile, impact, and flexural properties of thermoplastic composites, viz. sisal-polypropylene and sisal polystyrene, is explained here, and the change in fiber volume also given here. 

Properties of randomly orientation of sisal fiber composites are shown in parentheses) PP Polypropylene PS Polystyrene... 

Antich P, Vazquez A, Mondragonb I et al (2006) Mechanical behavior of high impact polystyrene reinforced with short sisal fibers. Compos A 37 139-150... 

Nair K C M, Kumar R P, Thomas S, Schit S C and Ramamurthy K (2000) Rheological behavior of short sisal fiber-reinforced polystyrene composites. Compos Part A 31 1231-1240. 

Ramires EC, Megiatto JD Jr, Gardrat C, Castellan A, Erollini E (2010) Biobased composites from glyoxal-phenolic resins and sisal fibers. Bioresour Technol 101 1998-2006 Reddy MM, Vivekanandhan S, Misra M, Bhatia SK, Mohanty AK (2013) Biobased plastics and bionanocomposites current status and future opportunities. Prog Polym Sci 38 1653-1689 Rojas OJ, Montero GA, Habibi Y (2009) Electrospun nanocomposites from polystyrene loaded with cellulose nanowhiskers. J Appl Polym Sci 113 927-935 Rowell RM (2012a) Chemical modification of wood to produce stable and durable composites. Cell Chem Technol 46 443 148... 

Table 7.3 Comparison of the tensile properties of longitudinally and randomly oriented solution-mixed sisal fiber-reinforced polypropylene (PP), polystyrene composites, and low density polyethylene (LDPE) (fiber length 6 mm).

The thermal stability of polystyrene composites reinforced with short sisal fibres was found to be better than that of sisal fibre and the PS matrix [a.288]. The effects of fibre loading, length, orientation and modification on the dynamic mechanical properties of the composites were evaluated. Benzoylation, maleic anhydride coating of the polystyrene and acetylation of the fibres were fibre modifications and treatments that were carried out to improve fibre/matrix adhesion through specific interactions of the macrochains. The Tg values of the composites were lower than that of unreinforced PS, and this effect was attributed to the presence of some residual solvent in the composites entrapped during composite preparation. However, the composites with treated fibres showed better thermal degradation properties than those with untreated fibres. 

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