Polybutylene Adipate Terephthalate Research Articles

Poly(lactic acid)-based Composites Incorporated with Spent Coffee Ground and Tea Leave for Food Packaging Application: A Waste to Wealth

Polymer composites of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) incorporated with spent coffee grounds (SCG) and tea leave (TL) were prepared by two-roll mill mixer. 4,4-methylene diphenyl diisocyanate (MDI), toluene 2,4-diisocyanate (TDI), and bis[3-(triethoxysilyl) propyl] tetrasulfide (TESPT) were used as coupling agents. The influences of coupling agent types, coupling agent content, and weight ratios of polymer to filler on the mechanical properties, melt flow index, and overall migration (OM) of the composites were studied. The results showed that MDI and TDI had better performance compared to TESPT for both tensile and elongation at break. The tensile strength and elongation at break of PLA+PBAT/SCG composites with weight ratio of polymer to filler = 70/30 increased from 19.6 MPa to ∼23.0 to 25.0 MPa, and 6.6 to ∼10.0%, respectively when using these coupling agents (MDI and TDI) of 3 g/100 g polymers. Moreover, the addition of MDI and TDI greatly increased the viscosity of the melted composites (4-fold), while TESPT made the viscosity decrease. However, the mechanical properties of the composites decreased drastically with increasing SCG proportion. Compared to PLA+PBAT/SCG, interfacial adhesion of PLA+PBAT/TL was higher confirming by tensile strength and SEM images. However, there was no significant difference between PLA+PBAT/TL and PLA+PBAT/SCG composites in terms of elongation at break, impact strength and melt flow index. The OM of PLA+PBAT/SCG and PLA+PBAT/TL composites with coupling agents were in the range of ∼0.03–0.28 mg/dm2 when using 3% acetic acid and 10% ethanol as food simulants, which not excess the migration limit (10 mg/dm2) according to Food Contact Materials EU No. 10/2011 legislation. It means that they might be safe for use as food contact materials for packaging and containers.

Optimizationof poly(L-lactide)-polybutylene adipate terephthalate diblockcopolymer by ring opening polymerization

Polylactide (PLA) is a brittle biodegradable polymer: co-bonding of a higher flexibility polymer such as polybutylene adipate terephthalate (PBAT) into the PLA chains has been shown to make it more flexible. We studied the optimum conditions for synthesizing poly(L-lactide)-polybutylene adipate terephthalate diblock copolymer (PLLA-b-PBAT), with ratios by weight of L-lactide:PBAT from 100:0.3 to 100:1. Incubation times of polymerization were varied from 4 to 8 hours at 160°C. Nuclear magnetic resonance (NMR) spectra were used to verify the structure of synthesized polymers. Differential scanning calorimetry thermograms showed melting temperatures of diblock copolymers at around 161-168°C - characteristic of PLA. The optimum conditions for PLLA-b-PBAT synthesis by ring opening polymerization were 100:0.3 ratio and eight hour incubation leading to 95% yield, a high degree of crystallinity (71%) and the highest molecular weight (34,000g/mol, measured by gel permeation chromatography).

Novel tunable super-tough materials from biodegradable polymer blends: nano-structuring through reactive extrusion.

Structuring blends on sub-micrometer scales, especially nano-scales, has a higher potential for improving their thermomechanical properties. Here, we propose a design strategy to fabricate compatible nano-blends by manipulating the reactions between two biodegradable polymers, e.g. polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), with extremely low free radical contents through reactive extrusion processing. Observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM), it is found that PBAT is tightly surrounded by large amounts of PBS–PBAT co-polymers and dispersed in a PBS matrix with a particle size of less than 100 nm. We show how impact strength and polymer moduli can be improved simultaneously by decreasing the small amount of dispersed phase into nano-scale (droplet or lamina structures). With 5 wt% PBAT content in the PBS–PBAT blend, the notched impact strength of PBS is increased 1200% and the Young's modulus is increased 15%. Through in situ rheological monitoring and Fourier-transform infrared spectroscopy (FTIR) studies, the reason why nano-blends can be formed in such a low amount of peroxide is illustrated. Our investigation most significantly indicates the transformation of the partially compatible PBS–PBAT micro-blend into a fully compatible PBS–PBAT through nano-structuring. This work addresses the importance of reaction rate and mechanism in favoring the formation of co-polymers rather than homo-polymer crosslinking or self-decomposition in polymer blend modification via reactive extrusion design.

Biodegradable Composites Developed from PBAT/PLA Binary Blends and Silk Powder: Compatibilization and Performance Evaluation.

Silk fibroin powder and biodegradable polybutylene adipate terephthalate (PBAT)/poly lactide (PLA) blends were melt-mixed together to fabricate natural and synthetic polymers as possible new sources of biomaterials. Morphological observations conducted through scanning electron microscopy indicated poor dispersion of the silk powder agglomerates, which resulted from strong hydrogen interactions between silk powder chains in the PBAT/PLA matrix. Although the silk powder agglomerates decreased the mechanical properties, as silk powder fractions increased, the ternary blend with 10 wt % silk powder still displayed high impact strength of 108 J/m and tensile modulus of 1.2 GPa. On the basis of mechanical analysis, this blend offered potential applications in fields which required high impact strength. Blends which contained Joncryl experienced a decrease in storage modulus. Furthermore, rheological studies confirmed that the viscosity of the PBAT/PLA/Silk powder blends decreased, which indicated possible weakening of hydrogen bonds between the silk chains, caused by the reaction between the epoxy groups of Joncryl. This reaction provides a possible method to improve the processability of this natural polymer and to improve its distribution in polymer blends.

Optimization of tensile properties thermoplastic blends from soy and biodegradable polyesters: Taguchi design of experiments approach

Soy meal-based biodegradable blends were prepared by melt extrusion process. The effects of denaturants, i.e., urea and sodium sulfite and plasticizer (glycerol) and polyester type (polybutylene succinate, polycaprolactone, polybutylene adipate terephthalate) on tensile strength and elongation at break were investigated using a Taguchi experimental design approach. The results showed that the sodium sulfite had little or no effect on final properties of the blends. Also, biodegradable polyester type had significant effect on the tensile strength and elongation at break of the blends prepared. The predicted values and experimental were found to be in tune with each other. The chemical structure and morphology of the optimum sample was probed by FT-IR spectroscopy and scanning electron microscopy (SEM). Also, the results provided an insight into how important the plasticization and destructurization of soy protein to obtain the blends with desired mechanical properties.

In situ lamination of starch‐based baked foam packaging with degradable films

AbstractA technique for making biodegradable food service packaging comprising a starch–fibre core and a biodegradable film laminate is described. The biodegradable films were made of polylactic acid (PLA), polybutylene succinate/terephthalate (PBST), rubber latex and polybutylene adipate/terephthalate (PBAT). The technique involved an in situ process for laminating a baked foam product in a single step. A critical element of the in situ technique involved using a heat insulating fibre sheet to stabilize heat‐sensitive laminate films during the baking/lamination process. The PLA‐, PBST‐ and PBAT‐laminated samples were baked for 6min at 120°C. The latex‐laminated sample, which was much more heat‐stable, did not need the insulating sheet and was baked for 3min at 160°C. Starch‐based foam laminated with PLA, PBST or PBAT generally had higher density and greater tensile and flexural strength than the non‐laminated control. Starch foam laminated with a rubber latex film had tensile and flexural properties similar to the non‐laminated control, due to the low modulus and elasticity of the latex film. The in situ lamination process improved the adhesion of the starch foam core with the fibre sheet, PLA and latex films compared to a post‐lamination process. All of the laminate materials provided a low water vapour permeance. The films degraded in a compost mixture but at a much slower rate compared to starch. Copyright © 2006 John Wiley & Sons, Ltd.

Correlation between mechanical adhesion and interfacial properties of starch/biodegradable polyester blends

AbstractBiopolymers are preferred ingredients for the manufacture of materials because they are based on abundantly available and renewable raw materials that have benign environmental problems associated with their production, fabrication, use, and disposal; however, the wide use of biopolymers in engineering applications has not been achieved, mainly because of the inferior quality of many biopolymer‐based products. To overcome this limitation, studies have been initiated on blends of biopolymers and biodegradable synthetic polymers. We used the contact angle of probe liquids to measure the surface energy of polystyrene, the biodegradable polyesters polycaprolactone, poly(hydroxybutyrate‐co‐hydroxyvalerate), polylactic acid, polybutylene adipate terephthalate, and adipic poly(hydroxy ester ether), and normal starch. The surface energies were used to estimate the starch/polymer interfacial energy and work of adhesion. The calculated starch/polyester work of adhesion showed mixed correlation with published starch/polyester mechanical properties, indicating that factors other than interfacial properties might be dominant in determining the mechanical properties of some starch/polyester blends. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 920–930, 2001