Improved Impact Properties in Poly(lactic acid) (PLA) Blends Containing Cellulose Acetate (CA) Prepared by Reactive Extrusion

Abstract

Poly(lactic acid)/triacetine plasticized cellulose acetate (PLA/pCA) blends were prepared by extrusion at two different temperatures and tetrabutylammonium tetraphenyl borate (TBATPB) was added as a transesterification catalyst to reactively promote the formation of PLA-CA copolymer during the reactive extrusion. The occurrence of chain scission in the PLA phase and branching/crosslinking in the CA phase in the presence of TBATPB, resulting also in a darkening of the material, were demonstrated by studying torque measurements and by performing proper thermogravimetric tests on CA with the different additives. Tensile and impact tests onto the blends prepared at the lower temperature showed better properties than the ones obtained at a higher temperature. Then, the mechanical properties of PLA/plasticized cellulose acetate (pCA) blends prepared at the lower temperature were investigated as a function of the content of plasticized CA in the blend. A range of compositions was observed where blends exhibited improved impact properties with respect to pure PLA without a significant decrease in their elastic modulus. The study of the phase morphology of the blends revealed that the occurrence of reactive compatibilization did not significantly affect the phase distribution. In general, fibrillar CA particles were formed in the PLA matrix during extrusion, thus allowing the preparation of CA fibre reinforced composites. The trend of morphology as a function of the composition and processing conditions was then discussed by considering the evolution of phase morphology in immiscible polymer blends.

Preparation and evaluation mechanical, chemical and thermal properties of hybrid jute and coir fibers reinforced bio-composites using poly-lactic acid and poly-caprolactone blends

“…Similarly, optimized samples B-1 , and C-1 demonstrating the lowest impact strength due to the failure of moist fibers thoroughly while other optimized samples were exhibiting moderate results in the experimental group. Besides, pure PLA exhibited the lowest result over other optimized samples attributed to blending PLA with other substances improves the impact toughness, although proper melting turns PLA into more brittle material [44]. As a result, an optimized sample of fiber content 40% B-2 demonstrating 26.08% from optimized sample B-2 and 15.52% from C-2 reduced impact strength within the experimental group.…”

Cosmetic Packaging to Save the Environment: Future Perspectives

“…PLA blends containing cellulose acetate are even very promising for rigid packaging and fully biodegradable depending on the cellulose acetate acetylation degree and of its content in the blend [33]. Recently, composites consisting of PLA reinforced with plasticized cellulose acetate were obtained by extrusion reporting an improvement of toughness with respect to raw PLA, while maintaining a high value of Young's Modulus [34].…”

Integrated and Consolidated Review of Plastic Waste Management and Bio-Based Biodegradable Plastics: Challenges and Opportunities

“…In addition, the degradation of PLA progresses faster above its glass transition temperature, which is around 55 to 60 • C [163][164][165], with high moisture content and microbes. Therefore, under home composting it degrades slowly, which necessitates the need for controlled conditions in an industrial composting setup [88,91] for its end of life disposal.…”

“…The other drawbacks of PLA are its high brittleness, with an elongation at break of 4 to 7% compared to PET with 20% [167], and low heat distortion temperature of 55 • C versus 116 • C for PET [88,167], which limit the areas of application of this polymer. Furthermore, due to the polymer's low glass transition temperature, it cannot be used where stiffness at high temperatures is needed, for example, in the manufacture of containers for hot drinks or automotive industry [165]. Hence, it is blended with other bio-based and/or biodegradable plastics to improve its properties.…”