Theoretical and analyzed data related to thermal degradation kinetics of poly (L-lactic acid)/chitosan-grafted-oligo L-lactic acid (PLA/CH-g-OLLA) bionanocomposite films

The theoretical and analyzed data incorporated in this article are related to the recently published research article entitled “Thermal degradation behaviour of nanoamphiphilic chitosan dispersed poly (lactic acid) bionanocomposite films” (http://dx.doi.org/10.1016/j.ijbiomac.2016.11.024) (A.K. Pal, V. Katiyar, 2016) [1]. Supplementary information and data (both raw and analyzed) are related to thermal degradation kinetics and explains various model fitting and is conversional methods, which are used in this research work to enhance the knowledge about degradation behaviour of PLA/CH-g-OLLA bionanocomposite system. Non-isothermal degradation kinetics of such polymeric system was proposed using Kissinger, Kissinger–Akahira–Sunose, Flynn–Wall–Ozawa and Augis and Bennett models to estimate the activation energies (Ea) and R2 values

Cellulose Functionalized High Molecular Weight Stereocomplex Polylactic Acid Biocomposite Films with Improved Gas Barrier, Thermomechanical Properties

This work presents a facile, solvent-free approach for the fabrication of PLA biocomposites, followed by melt extrusion process to prepare stereocomplex PLA films with excellent thermomechanical and gas barrier properties. The presence of stereocomplex crystallites improves the thermal properties of polylactic acid (PLA); however, the formation of stereocomplex crystallites is predominantly lesser compared to homocrystallites in case of high molecular weight poly­(l-lactic acid) and poly­(d-lactic acid) blend. Grafting of biofillers with polymer matrix chains may help in homogeneous dispersion and formation of stereocomplex crystallites. Henceforth, stereocomplex PLA was fabricated with cellulose microcrystals (CMC) as filler, after chemical modification by in situ ring opening polymerization of d-lactide. The stereocomplexation in the blend system was found to be enhanced by the extended molecular surface area provided by grafted CMC. As confirmed by morphological analysis, the modification of CMC drives the homogeneous dispersion into the matrix and reduction in the size of CMC in the range of ∼200 nm diameter. Increased melting temperature (∼209 °C) with no evidence of homocrystallites confirm the role of grafted CMC in the formation of stereocomplex crystallites by suppressing the development of homocrystals. The fraction of stereocomplex crystallites was found to be 100% when analyzed using X-ray analysis. The enhanced stereocomplexation in the composites resulted ∼96% improvement in the tensile strength in comparison to pristine PLLA/PDLA blend. Interestingly, the oxygen permeability and water vapor permeability were reduced by ∼25% and ∼35%. The improved thermomechanical properties of the biocomposites through enhanced stereocomplexation may comply with the requirement for high temperature engineering and packaging applications

Electrospun chitosan coated polylactic acid nanofiber: A novel immobilization matrix for α – Amylase and its application in hydrolysis of cassava fibrous waste

This present study addresses the uncherished resource potential of Cassava fibrous waste (CFW) from the cassava processing industry towards production of fermentable sugars using enzymatic hydrolysis process. However, the viscous nature of the gelatinized CFW poses serious processability issues, which was overcome by a novel attempt of using tailor-made electrospun nanofibers and its application in immobilization of α – amylase. Characterization studies (FESEM, FTIR, Thermogravimetric analysis), rheological and proximate analysis of CFW revealed its suitability as the potential feedstock. Chitosan coated nanofiber (CCN) matrix was prepared by varying the chitosan concentration from 0 to 2% (w/v) and the 2% CCN matrix exhibited an optimal performance with enhanced tensile strength (1.262 MPa), reduced elongation (41.2%) and contact angle (128°). CCN matrix was examined for the immobilization of α - amylase enzyme and the relative activities of the immobilized and free enzyme were compared. Packed bed operation at optimized conditions (solution pH of 5.0 and a solution temperature of 50 °C) deploying CCN matrix with initial substrate concentration of 10 g/l yielded a maximum conversion ratio of 0.85 and 0.99 (high residence time of 40 min and low dilution rate of 0.04 min−1) for without and with recycling mode, respectively

Protic acid assisted synthesis of new materials from a carbon dioxide derived disubstituted lactone precursor

The exploitation of carbon dioxide as a feedstock for the synthesis of disubstituted lactones has witnessed an enormous recognition lately. Several attempts have recently been made to employ disubstituted lactones into the chemistry of polymerization by overcoming their thermodynamic stability. The current research reveals the cationic polymerization of carbon dioxide derived disubstituted lactone (α-ethylidene, δ-vinylvalerolactone: EVV) in the presence of a highly reactive protic acid via a solvent-free process. A reaction mechanism for the protic acid assisted polymerization of EVV is proposed, where the vinyl group undergoes reaction to form polymers having a short chain length followed by chain transfer resulting in olefinic terminals. The cationic polymerization product undergoes hydrolysis to form a polymeric structure with hydrolyzed side groups, followed by dehydration resulting in a carboxyl group and an olefinic moiety in the side groups. The molecular weight and structure of the cationic polymerization product are determined by MALDI-TOF mass spectrometry and NMR spectroscopic analyses. The application of metal-free initiating system into the polymerization of carbon dioxide derived disubstituted lactone thus results in the formation of new materials that may serve as essential benchmarks for the sustainable future chemistry

Magnetic Cellulose Nanocrystal Based Anisotropic Polylactic Acid Nanocomposite Films: Influence on Electrical, Magnetic, Thermal, and Mechanical Properties

This paper reports a single-step co-precipitation method for the fabrication of magnetic cellulose nanocrystals (MGCNCs) with high iron oxide nanoparticle content (∼51 wt % loading) adsorbed onto cellulose nanocrystals (CNCs). X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopic studies confirmed that the hydroxyl groups on the surface of CNCs (derived from the bamboo pulp) acted as anchor points for the adsorption of Fe₃O₄ nanoparticles. The fabricated MGCNCs have a high magnetic moment, which is utilized to orient the magnetoresponsive nanofillers in parallel or perpendicular orientations inside the polylactic acid (PLA) matrix. Magnetic-field-assisted directional alignment of MGCNCs led to the incorporation of anisotropic mechanical, thermal, and electrical properties in the fabricated PLA–MGCNC nanocomposites. Thermomechanical studies showed significant improvement in the elastic modulus and glass-transition temperature for the magnetically oriented samples. Differential scanning calorimetry (DSC) and XRD studies confirmed that the alignment of MGCNCs led to the improvement in the percentage crystallinity and, with the absence of the cold-crystallization phenomenon, finds a potential application in polymer processing in the presence of magnetic field. The tensile strength and percentage elongation for the parallel-oriented samples improved by ∼70 and 240%, respectively, and for perpendicular-oriented samples, by ∼58 and 172%, respectively, in comparison to the unoriented samples. Furthermore, its anisotropically induced electrical and magnetic properties are desirable for fabricating self-biased electronics products. We also demonstrate that the fabricated anisotropic PLA–MGCNC nanocomposites could be laminated into films with the incorporation of directionally tunable mechanical properties. Therefore, the current study provides a novel noninvasive approach of orienting nontoxic bioderived CNCs in the presence of low magnetic fields, with potential applications in the manufacturing of three-dimensional composites with microstructural features comparable to biological materials for high-performance engineering applications