Elsevier

Journal of Cleaner Production

Volume 52, 1 August 2013, Pages 392-401
Journal of Cleaner Production

Surface treated banana fiber reinforced poly (lactic acid) nanocomposites for disposable applications

https://doi.org/10.1016/j.jclepro.2013.03.033Get rights and content

Highlights

  • Banana fiber (BF) was successfully used as filler for preparing PLA biocomposite.

  • Surface treatments of BF promoted the interfacial interaction in the biocomposite.

  • Cloisite 30B reinforced the biocomposite further to higher properties.

  • Better performance characteristics were reported for bionanocomposite than PLA.

  • Industrial trials were conducted for cutlery fabrication using bionanocomposite.

Abstract

Polylactic acid (PLA) is a completely biodegradable potential replacement for petroleum based plastics used for various commodity applications. However, difficulties in processability and cost restrict the polymer to clinch its niche in the market. Present investigation tried to modify the processability and cost of the PLA without compromising its inherent highlighted properties like good mechanical performances and biodegradability. Chemically treated banana fiber (BF) and organically modified nanoclay (cloisite 30B) has been incorporated as reinforcing fillers within the PLA matrix by melt mixing method. Various silane coupling agents and NaOH have been used for the chemical modification of BF to improve the interfacial interaction with PLA macromolecules. Performance characteristics of optimized composition of BF reinforced PLA bionanocomposite was evaluated through mechanical, thermal and flammability characteristics. Further, the newly developed bionanocomposite has been used for preparing biodegradable cutlery under industrial conditions.

Introduction

Biodegradable composites and nanocomposites of polylactic acid (PLA) have been extensively studied by several researchers for past two decades. Wollerdorfer and Bader (1998) have reported preparation and characterization of composites from l-Polylactide and natural fiber (Wollerdorfer and Bader, 1998). The author has been prepared biocomposites by melt blending method and reported improved mechanical performance for PLA matrix. Sinha et al. (2002), Pluta et al. (2002), Mohanty et al. (2000), etc, have been also identified significance of PLA as its nanocomposites and natural fiber reinforced composites for different end use applications (Sinha et al., 2002; Pluta et al., 2002; Mohanty et al., 2000). PLA is known for good mechanical properties, transparency and biodegradability characteristics. However, it is also known for poor processability and brittleness nature. As a result, majority of the studies on PLA were concentrated on the modification of these drawbacks.

Natural fiber reinforced PLA biocomposites are one of the much discussed area of research among the material scientists in recent years. Jute, banana, bamboo, pineapple leaf etc. are the most commonly using natural fiber as reinforcement within the PLA matrix (Oksman et al., 2003; Luo and Netravali, 1999; Okubo and Fujii, 2002). However, poor interfacial interaction in between the matrix and natural fiber is a pondering subject for material scientists in this area.

Surface modification of natural fiber is a method to improve the interfacial interaction between the matrix PLA and natural fiber. Kalaprasad et al. (1997) has reported various chemical modifications of natural fiber which provides better interface within the biocomposites (Kalaprasad et al., 1997).

Sometimes, surface modifications of natural fiber alone may not promote the properties biocomposites to the required level for end use applications. This may be due to the larger interstitial voids created within the biocomposites during the reinforcement of natural fiber. Such voids can accelerate premature breakage during mechanical testing. In such cases intercalation/exfoliation of organically modified layered silicates within the biocomposite system can be a good method to regain/boost the performance characteristics of the biocomposite. Biswal et al. (2009), has reported a similar study with improved mechanical and thermal properties of pineapple leaf fiber reinforced polypropylene nanocomposites (Biswal et al., 2009).

In the view of above observations, current study has been attempted to prepare and characterise BF and cloisite 30B (C30B) reinforced bionanocomposites using PLA matrix. BF was chemically modified using coupling agents like 3-Aminopropyltriethoxysilane (APS) and [bis-(3-triethoxysilylpropyl) tetrasulfane] (Si69) and also mercerized using NaOH to enhance the compatibility with the matrix. Susequently, PLA/BF biocomposites have been prepared by melt mixing method. Further, organically modified layered nanosilicate, cloisite 30B (C30B) has been reinforced within the PLA/BF biocomposites with optimized composition. The biocomposites and bionanocomposites were characterized by mechanical, thermal, morphological and flammability studies.

Section snippets

Materials

Poly-lactic acid (PLA 4042 D), obtained from M/s Nature Works LLC, was used as base matrix with a molecular weight around (Mw) 165,000 g/mol. Banana fiber (Musa sepentium) obtained from M/s Tripura Mushroom Growers welfare Society, Tripura, India, with a density of 1.35 g/cc was used as reinforcement material. Surface modifiers, 3-aminopropyltriethoxysilane (APS), a product of M/s Evonic Degussa (China) Co. Ltd supplied by Aroma Chemical Agencies (India) Pvt. Ltd. and bis-(3-triethoxy silyl

Surface modification of banana fiber (BF)

Banana fibers, in the form of bundles were cut into a length of 13–15 cm, and scoured in mild detergent solution at 60 °C for about 2 h to remove dust and other impurities. Finally, the fibers were washed in distilled water and dried in air for 2 days. Detergent washed fiber is denoted as ‘UBF’ within the whole study.

Mercerization or NaOH treatment

Mercerization of the fibers was carried out by immersing the fibers in 1N sodium hydroxide (NaOH) solution for 1 h at room temperature. Then the fiber washed with distilled water

Confirmation of surface treatments of banana fiber using FT-IR

Fig. 1 shows FT-IR spectra of untreated and chemically modified BF. The expected changes by surface modifications using NaOH and silane coupling agents are given in Fig. 2a. As the main components of natural fiber are cellulose, hemicelluloses and lignin, the observed FT-IR spectra of untreated and all the treated BF featured mainly of these components. Peak in the region of 1030–1150 cm-1 is primarily due to C–O–C and C–O stretching in the cellulose, lignin and their glycoside linkages.

Conclusion

Eco-friendly biodegradable cutlery has been prepared successfully using optimised composition of surface treated BF reinforced bionanocomposite. Mechanical, thermal and flammability study has been proved that the newly developed material has better or comparable properties with petroleum based polymers. Surface treatments of banana fiber have been proved to be acceptable way of enhancing the interfacial interaction in between PLA and BF. In addition, the newly added functionalities, especially

References (17)

  • D. Plackett et al.

    Biodegradable composites based on polylactide and jute fibers

    Compo. Sci. Tech.

    (2003)
  • M. Wollerdorfer et al.

    Influence of natural fibers on the mechanical properties of biodegradable polymers

    Indu. Crop Prod.

    (1998)
  • M. Biswal et al.

    Influence of organically modified nanoclay on the performance of pineapple leaf fiber-reinforced polypropylene nanocomposites

    J. Appl. Polym. Sci.

    (2009)
  • P.V. Joseph et al.

    The effect of processing variables on the physical and mechanical properties of short sisal fibre reinforced polypropylene composites

    Compo. Sci. Tech.

    (1999)
  • G. Kalaprasad et al.

    Influence of short glass fibre addition on the mechanical properties of sisal reinforced low density polyethylene composites

    J. Comp. Mate.

    (1997)
  • S. Luo et al.

    Interfacial and mechanical properties of environment-friendly green composites made from pineapple fibers and poly(hydroxybutyrate-co-valerate) resin

    J. Mate. Sci.

    (1999)
  • P. Maiti et al.

    Biodegradable polyester/layered silicate nanocomposites

    Mater. Res. Soc. Symp. Proc.

    (2002)
  • A.K. Mohanty et al.

    Biofibres, biodegradable polymers and biocomposites: anoverview

    Macrmol. Mater. Eng.

    (2000)
There are more references available in the full text version of this article.

Cited by (97)

  • Isothermal crystallization kinetics and mechanical properties of PLA/Kenaf biocomposite: Comparison between alkali treated kenaf core and bast reinforcement

    2022, Materials Letters
    Citation Excerpt :

    However, it has some disadvantages, including its inability to withstand high temperatures and the relatively slow crystallization that prolongs its production process. One proposed strategy to overcome these drawbacks is the addition of natural fibers such as kenaf as a reinforcement agent [1]. Kenaf stem, which is the fibrous part of the plant, comprises of bast and core.

View all citing articles on Scopus
View full text