The effect of polystyrene-block-poly(ethylene-ran-butylene)-block-poly(strene- graft-maleic-anhydride) as compatibilizing agent (2 and 4%) and alkali treatment (4 and 6%) of short SPF on the flexural strength and flexural modulus of SPF/ HIPS composites were studied by Bachtiar et al.116 using 40 wt.% of fiber content. SPF alkali treatment using 6% NaOH solution improved the flexural strength, flex­ural modulus and impact strength of the composites as compared to the untreated composites by 12%, 19% and 34%, respectively. On the contrary, the SPF/HIPS composites treated with compatibilizing agent indicated no improvement in flex­ural strength and flexural modulus. However, significant improvements of impact strength of the alkali and compatibilizing agent treated composites were obtained. The impact strength of the 4% alkali and 3% compatibilizing agent treated compos­ites were about 16% higher than the untreated SPF/HIPS composites. The enhance­ment of the impact strength of alkali treated SPF/HIPS composites were due to: (1) development of rough surface fibers which offers good fiber-matrix adhesion; and (2) removal of hemicellulose and lignin parts of the SPF fibers, whereas the strong cellulose components on the fibers remained. The compatibilizing agent also en­hanced the impact strength of the composites due to chemical reaction of hydroxyl groups of SPF fibers with the anhydride groups of the copolymers which resulted into good interface adhesion between SPF fiber and HIPS matrix.116

9.4 CONCLUSIONS

The rapid advancement in the development of greener materials based on natural fibers and biopolymers is gaining more attention due to increase environmental awareness coupled with depletion of petroleum resources. Utilization of fibers and polymers that are biodegradable and obtained from renewable resources will help to preserve our environment. Hence, sugar palm tree is a potential ‘green resource’ for natural fibers and biocomposites.

Sugar palm tree is one of the multipurpose trees grown in tropical regions. Of recent, sugar palm fiber with its desirable properties has manifested high potential to be used as reinforcement in polymer composites. Sugar palm fibers can be used as reinforcement for bio-based polymers to produce 100% biodegradable compos­ites. The use of sugar palm fiber and bio-based polymers or even petroleum-based polymers to develop greener composites helps in: (1) reducing the negative environ­mental impact of synthetic polymers and fibers; (2) decreasing the pressure for the dependence on petroleum products; and (3) developing sugar palm trees as new crop in the future for tropical countries most especially in Malaysia. When biocomposite materials from sugar palm tree are increasingly used for industrial applications, such would boost Malaysia’s status as global promoter, developer and manufacturer of green composites. This would lead to increasing revenues and create more jobs. The successful development of green composites from sugar palm tree would provide opportunities to improve the standard of living of the sugar palm tree farmers in Ma­laysia. These would generate nonfood source of economic development for farming and rural areas in Malaysia.

9.5 ACKNOWLEDGEMENTS

The authors wish to acknowledge the financial support from Ministry of Education Malaysia with Exploratory Research Grant Scheme (ERGS) project vote number 5527190. Thanks also due to Universiti Putra Malaysia for granting sabbatical leave to S. M. Sapuan in 2013-2014 and to Ministry of Education Malaysia for scholar­ship award (MyPhD) to J. Sahari. The assistance of Dr. Nukman Yusoff of Universiti Malaya is highly appreciated.