Grewia optiva

Singha, A. S., Thakur, V. K., Mishra, B. N. (2009). Study of grewia optiva fiber reinforced urea-formaldehyde composites, J. Polym. Mater, 26(1), 81-90. 

Flax Fibers Sisal Fibers Pine Fibers Grewia Optiva Hemp Fibers... 

A.S. Singha and V.K. Thakur, Synthesis and characterization of grewia optiva fiber-rein-forced PF-based composites. Int. /. Polym. Mater. 57, 1059-1074 (2008). 

A. S. Singha, and V. K. Thakur, Synthesis and characterizations of silane treated grewia optiva fibers. Int. J. Polym. Anal. Charact. 14,301-321 (2009). 

Keywords Grewia optiva, flammability, thermal stability, mechanical properties, UPE, benzoylation, FTIR... 

In the present chapter, we report some of om study on both raw and surface-modified Grewia optiva fiber-reinforced UPE matrix-based composites, which possess enhanced mechanical and physico-chemical properties when compared with UPE matrix. In addition to the effect of flame retardants, i.e., magnesium hydroxide and zinc borate, on flame resistance, the behavior of resulted Grewia optiva fiber-reinforced composites have also been evaluated and was foimd to be improved. A significant discussion on the work of other researcher s work has also been added in the chapter. 

Benzoylation of Grewia optiva fiber was carried out by using a 5 vol% benzoyl chloride in 10% alkali solution for 10-15 min as per procedure reported earlier [21]. Scheme 2 shows the possible mechanism for grafting of benzoyl chloride onto cellulosic fibers. 

Scheme 13.2 A possible mechanism for grafting of benzoyl chloride onto Grewia optiva fiber [22].

Figure 13.1 Tensile strength of different surface-modified Grewia optiva particle fibers-reinforced unsaturated polyester composites.

When reinforced with mercerized and benzoylated particle fibers. The UPE matrixhas been found to exhibit flexural strength of 55.26, 62.26, 66.29 and 57.26 MPa 61.7, 67.1, 69.52 and 62.32 MPa at 10,20,30 and 40% fiber loading, respectively. The results obtained were found to be consistent with results obtained in the case of AN graft copolymerized Grewia optiva fibers-reinforced unsaturated polyester composites [26]. Rai et al. have also reported similar results during their studies [16]. 

Figure 13.9 TGA curves for raw and surface-functionalized Grewia optiva fibers-reinforced unsaturated polyester matrix-based composites.

Table 13.1 % Water absorbance by neat UPE and its composites reinforced with particle and short form of raw, mercerized, silanated, benzoylated, Grewia optiva-g-poly (AN) and Grewia optivfl-g-poly-(AAc) fibers.

UPE Grewia optiva Ratio (% by weight) Fire Retardant (% by weight of UPE) LOI... 

It has been observed from the above discussion that mechanical, physico-chemical and fire retardancy properties of UPE matrix increases considerably on reinforcement with surface-modified natural cellulosic fibers. The benzoylated fibers-reinforced composite materials have been found to have the best mechanical and physico-chemical properties, followed by mercerized and raw Grewia optiva fibers-reinforced composites. From the above data it is also clear that polymer composites reinforced with 30% fibers loading showed the best mechanical properties. Further, benzoylated fibers-reinforced composites were also found to have better fire retardancy properties than mercerized and raw fibers-reinforced polymer composites. Fire retardancy behavior of raw and surface-modified Grewia optiva/GPE composites have been found to increase when fire retardants were used in combination with fibers. This increase in fire retardancy behavior of resulted composites was attributed to the higher thermal stability of magnesium hydroxide/zinc borate. 

A.S. Singha, and A.K. Rana, Effect ofaminopropyltriethoxysilane (APS) treatment on properties of mercerized lignocellulosic Grewia optiva fiber. /. Polym. Environ. 21, 141-150 (2013). 

The thermal behavior of the composites based on raw and surface modified Grewia optiva particle fibres reinforced unsaturated polyester matrix was studied [47]. The fibres were modified by mercerization, silanation, benzoylation and graft copolymerization. The thermal stability of the composites containing modified fibres was improved compared to the unsaturated polyester matrix and to the composites containing untreated fibres. This was a consequence of the additional intermolecular bonding between fibres and matrix induced by the surface modification. The highest thermal stability was obtained by the composites based on silanated fibres due to the formation of strong covalent bonds between silanes and cellulose. 

Singha, A.S., Rana, A.K., Jarial, R.K. Mechanical, dielectric and thermal properties of Grewia optiva fibers reinforced unsaturated polyester matrix based composites. Mater. Des. 51, 924-934 (2013)... 

Singha AS, Thakur VK, Mishra BN. Study of Grewia optiva fiber reinforced urea-form-aldehyde composites. J Polym Mater 2009 26 (l) 81-90. 

SCHEME 15.2 A schematic representation of various surface modifications of Grewia optiva fibers. Reprinted with permission from Ref. [20]. 2013 Elsevier. 

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