Poly(lactic acid)/poly(butylene succinate)/calcium sulfate whiskers biodegradable blends prepared by vane extruder: Analysis of mechanical properties, morphology, and crystallization behavior

2014 ◽  
Vol 34 ◽  
pp. 1-9 ◽  
Author(s):  
Rong-yuan Chen ◽  
Wei Zou ◽  
Cheng-ran Wu ◽  
Shi-kui Jia ◽  
Zan Huang ◽  
...  
Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky

Sugar beet pulp (SBP) is a residue available in large quantities from the sugar industry, and can serve as a cost-effective bio-based and biodegradable filler for fully bio-based compounds based on bio-based polyesters. The heterogeneous cell structure of sugar beet suggests that the processing of SBP can affect the properties of the composite. An “Ultra-Rotor” type air turbulence mill was used to produce SBP particles of different sizes. These particles were processed in a twin-screw extruder with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) and fillers to granules for possible marketable formulations. Different screw designs, compatibilizers and the use of glycerol as a thermoplasticization agent for SBP were also tested. The spherical, cubic, or ellipsoidal-like shaped particles of SBP are not suitable for usage as a fiber-like reinforcement. In addition, the fineness of ground SBP affects the mechanical properties because (i) a high proportion of polar surfaces leads to poor compatibility, and (ii) due to the inner structure of the particulate matter, the strength of the composite is limited to the cohesive strength of compressed sugar-cell compartments of the SBP. The compatibilization of the polymer–matrix–particle interface can be achieved by using compatibilizers of different types. Scanning electron microscopy (SEM) fracture patterns show that the compatibilization can lead to both well-bonded particles and cohesive fracture patterns in the matrix. Nevertheless, the mechanical properties are limited by the impact and elongation behavior. Therefore, the applications of SBP-based composites must be well considered.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1893 ◽  
Author(s):  
Přemysl Menčík ◽  
Radek Přikryl ◽  
Ivana Stehnová ◽  
Veronika Melčová ◽  
Soňa Kontárová ◽  
...  

This paper explores the influence of selected commercial plasticizers structure, which are based on esters of citric acid, on mechanical and thermal properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer biodegradable blends. These plasticizers were first tested with respect to their miscibility with Poly(3-hydroxybutyrate)/Poly(lactic acid) (PHB/PLA) blends using a kneading machine. PHB/PLA/plasticizer blends in the weight ratio (wt %) of 60/25/15 were then prepared by single screw and corotating meshing twin screw extruders in the form of filament for further three-dimensional (3D) printing. Mechanical, thermal properties, and shape stability (warping effect) of 3D printed products can be improved just by the addition of appropriate plasticizer to polymeric blend. The goal was to create new types of eco-friendly PHB/PLA/plasticizers blends and to highly improve the poor mechanical properties of neat PHB/PLA blends (with majority of PHB) by adding appropriate plasticizer. Mechanical properties of plasticized blends were then determined by the tensile test of 3D printed test samples (dogbones), as well as filaments. Measured elongation at break rapidly enhanced from 21% for neat non-plasticized PHB/PLA blends (reference) to 328% for best plasticized blends in the form of filament, and from 5% (reference) to 187% for plasticized blends in the form of printed dogbones. The plasticizing effect on blends was confirmed by Modulated Differential Scanning Calorimetry. The study of morphology was performed by the Scanning Electron Microscopy. Significant problem of plasticized blends used to be also plasticizer migration, therefore the diffusion of plasticizers from the blends after 15 days of exposition to 110 °C in the drying oven was investigated as their measured weight loss. Almost all of the used plasticizers showed meaningful positive softening effects, but the diffusion of plasticizers at 110 °C exposition was quite extensive. The determination of the degree of disintegration of selected plasticized blend when exposed to a laboratory-scale composting environment was executed to roughly check the “biodegradability”.


2017 ◽  
Vol 88 (14) ◽  
pp. 1616-1627 ◽  
Author(s):  
Shu-qiang Liu ◽  
Gai-hong Wu ◽  
Yun-chao Xiao ◽  
Hong-xia Guo ◽  
Fen-juan Shao

Poly(lactic acid) (PLA) fiber, owing to its biocompatibility and biodegradability, could be widely used in many related industrial areas. However, high brittleness has been the main obstacle to expanding its applications. So in this paper, carbon nanotube (CNT) nanocapsules were designed to toughen PLA and further reported their effect on the crystallization behavior and mechanical properties of PLA complex fiber. These designed CNT nanocapsules successfully solved the agglomeration of CNTs within the PLA matrix as well as the compatibility issue. In addition, the morphological, mechanical, optical and thermal properties of PLA complex fibers were also studied. The addition of CNT nanocapsules obviously improved the crystallization behavior of PLA fiber. Furthermore, compared with pure PLA, the tensile strength of PLA complex fiber was enhanced by 30.62% and the elongation by 32.2%, so the designed CNT nanocapsules could be used as a toughener for PLA fiber. This research benefits the extension of PLA applications where toughness is an important factor.


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