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This research was set out to explore the development of arrowroot starch (AS) films using glycerol (G) as plasticizer at the ratio of 15, 30, and 45% (w/w, starch basis) using solution casting technique. The developed films were analyzed in terms of physical, structural, mechanical, thermal, environmental, and barrier properties. The incorporation of glycerol to AS film-making solution reduced the brittleness and fragility of films. An increment in glycerol concentration caused an increment in film thickness, moisture content, and solubility in water, whereas density and water absorption were reduced. The tensile strength and modulus of G-plasticized AS films were reduced significantly from 9.34 to 1.95 MPa and 620.79 to 36.08 MPa, respectively, while elongation at break was enhanced from 2.41 to 57.33%. FTIR analysis revealed that intermolecular hydrogen bonding occurred between glycerol and AS in plasticized films compared to control films. The G-plasticized films showed higher thermal stability than control films. The cross-sectional micrographs revealed that the films containing 45% glycerol concentration had higher homogeneity than 15% and 30%. Water vapour permeability of plasticized films increased by an increase in glycerol concentrations. The findings of this research provide insights into the development of bio-degradable food packaging. [ABSTRACT FROM AUTHOR]

This study investigated the effects of pH, salinity, biomass concentration, and algal organic matter (AOM) on the efficiency of four commercial cationic flocculants. The tannin-based biopolymers Tanfloc SG and SL and the polyacrylamide polymers Flopam FO 4800 SH and FO 4990 SH were tested for flocculation of two microalgae models, the freshwater Chlorella vulgaris and the marine Nannochloropsis oculata. Both biomass concentration and AOM presence affected all polymers evaluated, whereas salinity and pH affected only Flopam and Tanfloc, respectively. A restabilization effect due to overdosing was only observed for Flopam polymers and increasing Tanfloc dose resulted in improved efficiency. Flopam polymers showed a significant decrease in the maximum quantum yield of photosystem II as function of polymer dose for Chlorella, which supported the need for toxicological studies to assess the potential toxicity of Flopam. In overall, Tanfloc was not affected by salinity nor presented potential toxicity therefore being recommended for the flocculation of both freshwater and marine species. [ABSTRACT FROM AUTHOR]

Methods of capillary viscometry, spectroscopy, and conductometry were used to investigate the compatibility of components in a biopolymer composite made of polyvinyl alcohol, products of enzymethermal degradation of collagen, and maltodextrin in aqueous solutions. The optimum proportion of maltodextrin ensuring high physicomechanical properties of biopolymer films was determined. [ABSTRACT FROM AUTHOR]

In this paper, the effects of lithium chloride (LiCl) on 1-allyl-3-methylimidazolium chloride (AMIMCl) and cellulose/AMIMCl were studied by steady-state and dynamic rheology experiments. After adding LiCl, a suprastructure may be formed in AMIMCl/LiCl because of fiber drawing and shear-thinning behavior. Moreover, the size of cellulose coil swelled by adding LiCl. In the master curve of cellulose-AMIMCl/LiCl solution, the critical overlap concentration was c = 0.63 and the entangled concentration was c = 2.27 for the entangled regime. Dependence of η on cellulose concentration in cellulose-AMIMCl/LiCl was η ∼ c and c in dilute and semi-dilute untangled regimes, respectively. Therefore, the AMIMCl/LiCl mixture was not a θ solvent for the neutral polymer. The solubility of cellulose decreased and degradation was aggravated after adding LiCl. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) is an important biodegradable polymer, used for numerous applications ranging from industrial packaging to tissue engineering. However, its inherent brittleness and limited thermal stability have restricted its penetration to niche markets. In this communication, the authors demonstrate that blending of PLA with castor oil-based polyurethane prepolymer (COPUP), with the addition of COPUP, dispersed in the PLA matrix can overcome the inherent brittleness of the matrix polymer. NCO-terminated COPUP was successfully synthesized and subsequently mixed with variable concentration of PLA matrix using melt blending technique. The interfacial compatibilization between COPUP and PLA phase happened by the reaction of −NCO groups with terminal hydroxyl groups of PLA was confirmed by FT-IR peak deconvolution technique. As indicated by the results of DMA and DSC, the glass transition temperature (Tg) of both PLA and COPUP shifted closer together, indicating that the blend compatibility increased. The tensile properties and notched Izod impact strength of the PLA and toughened PLA are also investigated. With the addition of 30 % COPUP concentration, the elongation at break of the blend reached 377.46 %, and a notched Izod impact 269.62 J m-1. With improved toughness, the PLA/COPUP blends could be used as replacements for some traditional petroleum-based polymers. [ABSTRACT FROM AUTHOR]

This paper investigates the enhancement of fly ash-based geopolymer with chitosan biopolymer. Unconfined compression and split tensile tests were carried out to investigate the effect of addition of small amount of N-carboxymethyl chitosan (0.05, 0.1, 0.15, and 0.2 wt% of fly ash) on the mechanical performance of fly ash-based geopolymer. Scanning electron microscopy (SEM) imaging was also conducted to study the microstructure of the chitosan enhanced fly ash-based geopolymer. The results indicated that the inclusion of N-carboxymethyl chitosan led to slight increase of the unconfined compressive strength and substantial increase of the tensile strength, the displacement at the peak tensile load and the pre-peak toughness, with the maximum increases at 0.1 wt% chitosan content. The SEM imaging indicated that the added N-carboxymethyl chitosan biopolymer coated and bridged the (geopolymerized) fly ash particles and led to the formation of a more condensed geopolymer network structure, thus enhancing the mechanical behavior of the geopolymer-biopolymer composite. However, when too much N-carboxymethyl chitosan was used, the excessive coating and encapsulation of un-reacted and partially hydrolyzed fly ash particles hindered their geopolymerization and adversely affected the mechanical behavior of the geopolymer-biopolymer composite. [ABSTRACT FROM AUTHOR]

The use of native starch as a thermoplastic polymer is limited by its fragility and high moisture absorption. Native potato starch was derivatized using different agents in order to reduce its hydrophobicity. A reduction in starch mechanical properties was also found as a side effect of derivatization treatments. The addition of nanocellulose allows to considerably improve mechanical properties of biopolymers as well as to maintain their inherent biodegradation capability. Cellulose nanofibers were added to native and modified starch in order to improve the mechanical properties. The mechanical properties of starch/cellulose nanocomposite films were evaluated, finding that they considerably improved with the addition of cellulosic nanofibers. This contribution demonstrates a new approach in order to produce bioplastics with combined effect: improved moisture and heat resistance (due to the chemical treatment) and high mechanical properties (after the addition of nanocellulose). [ABSTRACT FROM AUTHOR]