Poly lactic acid (PLA)/Banana fiber (BF) biocomposites were fabricated employing melt blending technique followed by compression molding. BF were surface‐treated by NaOH and various silanes viz. 3‐aminopropyltriethoxysilane (APS) and bis‐(3‐triethoxy silyl propyl) tetrasulfane (Si69) to improve the compatibility of the fibers within the matrix polymer. Mechanical tests revealed an increase of tensile strength to the tune 136% and impact strength to 49% as compared with the untreated biocomposite. Thermal properties of the composites have been evaluated using DSC and TGA. DSC thermograms revealed an increase in the melting transitions thus revealing effective fiber/matrix interface. The thermal stability in the biocomposites also increased in case of banana fiber treated with Si69. Viscoelastic measurements using DMA confirmed an increase of storage modulus and low damping values in the silane treated biocomposites. Biodegradation studies in the biocomposites have been investigated in B. cepacia medium through morphological and weight loss studies. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

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Partially miscible blends of poly(lactic acid) (PLA) and poly(hydroxybutyrate) (PHB) have been prepared by the melt mixing method. An interpenetrating network structure created by a maleic anhydride (MA) compatibilizer imparted additional interactions between the two matrices, which has resulted in increased miscibility within the blends. A modified interface has been characterized using morphological analysis through FT-IR and SEM analysis. Because MA compatibilization distributed flexible intermolecular hydrogen bonding within the blend matrix, elongation at break and Izod impact strength has been reported at a maximum of 540.17% and 99%, respectively, compared to those of the PLA matrix. Further, incorporation of layered silicates within the optimized composition of the PLA/PHB/MA blend modified the tensile strength by 49%, without compromising its superior flexible characteristics. Simultaneously, the renowned thermal insulating property of exfoliated/intercalated layered silicate works well to promote the thermal stability of the blend as well. Because two different nanoclays have been utilized in the present investigation, a comparative account of the extent of the intercalation/exfoliation has been reported through morphological analysis.

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Eco-friendly completely biodegradable biocomposites have been fabricated using polylactic acid (PLA) and banana fiber (BF) employing melt blending technique followed by compression moulding. BF's were surface treated by NaOH and various silanes viz. 3-aminopropyltriethoxysilane and bis-(3-triethoxy silyl propyl) tetrasulfane (Si69) to improve the compatibility of the fibers within the matrix polymer. Characterization studies have been suggested that a better fiber matrix interaction because of the newly added functionalities on the BF surface as a result of chemical treatments. In comparison with the untreated BF biocomposite, an increase of 136% in tensile strength and 57% in impact strength has been observed for Si69 treated BF biocomposite. DSC thermograms of surface treated BF biocomposites revealed an increase in glass transition and melting transition due to the more restricted macromolecular movement as a result of better matrix fiber interaction. The thermal stability in the biocomposites also increased in case of biocomposite made up of BF treated with Si69. Viscoelastic measurements using DMA confirmed an increase of storage modulus and low damping values for the same biocomposite. Biodegradation studies of the biocomposites have been investigated in Burkholderia cepacia medium through morphological and weight loss studies.

Agricultural mulch film of poly(lactic acid) (PLA) has been prepared under industrial conditions by the extrusion blown film method with modified properties using poly(hydroxibutyrate) (PHB) and reactive compatibilizer maleic anhydride (MA). Processing parameters and blend composition have been optimized based upon processability and mechanical properties of the final materials. Because PLA is a biopolymer, evaluation of service life period of the mulch film is very much important. Sustainability of the film has been analyzed by keeping the films in a weatherometer, which can create accelerated weather conditions, followed by mechanical testing at regular intervals. Similarly, variation in compostability has been analyzed as per the American standard for test method, ASTM D 5988, using vermi-compost. In addition, specific microbial action on the mulch films also has been analyzed using bacteria Berkholdaria cepacia (B. cepacia), which is selective in particular toward PLA degradation and in mixed fungal inoculums.

A love-mode surface acoustic wave (SAW) biosensor based on ST-cut quartz was developed for highly selective and label-free detection of carcinoembryonic antigen (CEA).The delay line area of an interdigital transducer (IDT) based SAW device was coated with gold and then chemically modified through thioglycolic acid-EDC/NHS reaction mechanism. A self-assembled monolayer of anti-CEA was further immobilized on the bioreceptors through the coupling layer. The biosensing capability of the SAW device was evaluated using solutions of CEA with various concentrations and limit of detection was obtained at 0.31 ng/ml of CEA, which is better than the results reported by the literatures available for CEA detection using SAW device. The real-time detection capability of the biosensor was evaluated using clinical serum samples and selectivity was evaluated using mixed solutions of CEA with other common tumor marking proteins. Long-term stability of the biosensor was also evaluated over a period of 30 days and the biosensing performance has shown only 8% decrease in performance within the whole period. The binding of CEA onto the bioreceptor was evaluated through Langmuir and Freundlich sorption isotherm kinetic studies as well.

Current study evaluates the effect of fiber surface treatments on the mechanical properties of banana fiber (BF) reinforced polylactic acid (PLA) biocomposites. Experimental results indicate increase in tensile modulus and strength upon surface treatments of BF with various silanes (APS and Si69) and NaOH. Approximately, an increase of 136% in tensile strength and 49% in impact strength was obtained in case of biocomposites with Si69‐treated BF compared with the untreated BF biocomposites. Also, experimentally determined mechanical modulus of untreated and surface‐treated BF biocomposite has been compared with the mechanical modulus calculated using various micromechanical models. Models such as Hirsch's, modified Bawyer and Bader's, and Brodnyan model showed good agreement with the experimentally determined results. Similarly, other models like Halpin‐Tsai, Nielson modified Halpin‐Tsai, and Cox's model also have been tried for the comparative study with the experimental data. Surface modification of BF showed increased interfacial adhesion between the fiber and the matrix which was evident from lowered difference between the experimentally and theoretically derived mechanical modulus. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013