scholarly journals Characterization of Different Chemical Blowing Agents and Their Applicability to Produce Poly(Lactic Acid) Foams by Extrusion

2018 ◽  
Vol 8 (10) ◽  
pp. 1960 ◽  
Author(s):  
Ákos Kmetty ◽  
Katalin Litauszki ◽  
Dániel Réti
Keyword(s):  
Lactic Acid ◽  
Cell Structure ◽  
Mechanical Tests ◽  
Poly Lactic Acid ◽  
Foaming Agent ◽  
Blowing Agents ◽  
Twin Screw ◽  
The Individual ◽  
Chemical Blowing Agents

This study presents the applicability of different types (exothermic and endothermic) of chemical blowing agents (CBAs) in the case of poly(lactic acid) (PLA). The amount of foaming agent is a fixed 2 wt%. We used a twin-screw extruder and added the individual components in the form of dry mixture through the hopper of the extruder. We characterized the PLA matrix and the chemical blowing agents with different testing methods. In case of the produced foams we carried out morphological and mechanical tests and used scanning electron microscopy to examine cell structure. We showed that PLA can be successfully foamed with the use of chemical blowing agents. The best results were achieved with an exothermic CBA and with PLA type 8052D. The cell population density of PLA foams produced this way was 4.82 × 105 cells/cm3, their expansion was 2.36, their density 0.53 g/cm3 and their void fraction was 57.61%.

Preparation and Characterization of Biodegradable Polylactic Acid/Gelatinized Cornstarch Foams

2011 ◽  
Vol 418-420 ◽  
pp. 86-89
Author(s):  
Peng Ping Xie ◽  
Ming Jun Niu ◽  
Kai Guo ◽  
Jin Zhou Chen ◽  
Xin Fa Li
Keyword(s):  
Lactic Acid ◽  
Poly Lactic Acid ◽  
Twin Screw Extrusion ◽  
Nucleation Agent ◽  
Blowing Agent ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Foam Properties ◽  
Optimized Conditions

Biodegradable foams derived from poly(lactic acid) (PLA) and gelatinized cornstarch (GS) were prepared by twin-screw extrusion using Azodicarbonamide(AC) as blowing agent and talc as nucleation agent. Foams with a relatively fine and uniform cell morphology and better foam properties were obtained under optimized conditions of PLA/GS ratio at 3:1, 1.5% AC content, and MAH and glycerol blend system.

Preparation and Characterization of Poly(Lactic Acid) (PLA)/Polyoxymethylene (POM) Blends

2018 ◽  
Vol 917 ◽  
pp. 3-6 ◽  
Author(s):  
Muhammad Haniff ◽  
Mohd Bijarimi ◽  
M.S. Zaidi ◽  
Ahmad Sahrim
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Chemical Analysis ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Twin Screw

PLA has limited applications due to its inherent brittleness, toughness and low elongation at break. One of the options for improvement is through blending with polyoxymethylene (POM). Melt blending of polylactic acid (PLA) and polyoxymethylene (POM) at 90/10 PLA/POM composition was carried out in a twin-screw extruder. The PLA/POM was loaded with 1 – 5 wt.% of nanoclay (Cloisite C20). The blends were then characterized for mechanical, morphological, chemical and thermal properties. It was found that tensile strength, Young's modulus, and elongation at break improved when the loadings of nanoclay were increased. Chemical analysis by FTIR revealed that PLA/POM blend is immiscible.

scholarly journals Dispersion of Micro Fibrillated Cellulose (MFC) in Poly(lactic acid) (PLA) from Lab-Scale to Semi-Industrial Processing Using Biobased Plasticizers as Dispersing Aids

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 896-915
Author(s):  
Giovanna Molinari ◽  
Vito Gigante ◽  
Stefano Fiori ◽  
Laura Aliotta ◽  
Andrea Lazzeri
Keyword(s):  
Lactic Acid ◽  
Mechanical Tests ◽  
Poly Lactic Acid ◽  
Scale Production ◽  
Dual Effect ◽  
Industrial Processing ◽  
Twin Screw ◽  
Poly Ethylene ◽  
Green Solution ◽  
Industrial Scale Production

In the present study, two commercial typologies of microfibrillated cellulose (MFC) (Exilva and Celish) with 2% wt % were firstly melt-compounded at the laboratory scale into polylactic acid (PLA) by a microcompounder. To reach an MFC proper dispersion and avoid the well-known aglomeration problems, the use of two kinds of biobased plasticisers (poly(ethylene glycol) (PEG) and lactic acid oligomer (OLA)) were investigated. The plasticizers had the dual effect of dispersing the MFC, and at the same time, they counterbalanced the excessive stiffness caused by the addition of MFC to the PLA matrix. Several preliminaries dilution tests, with different aqueous cellulose suspension/plasticizer weight ratios were carried out. These tests were accompanied by SEM observations and IR and mechanical tests on compression-molded films in order to select the best plasticizer content. The best formulation was then scaled up in a semi-industrial twin-screw extruder, feeding the solution by a peristaltic pump, to optimize the industrial-scale production of commercial MFC-based composites with a solvent-free method. From this study, it can be seen that the use of plasticisers as dispersing aids is a biobased and green solution that can be easily used in conventional extrusion techniques.

scholarly journals Observations of the effects of different chemical blowing agents on the degradation of poly(lactic acid) foams in simulated soil

2013 ◽  
Vol 16 (6) ◽  
pp. 1266-1273 ◽  
Author(s):  
Matheus V. G. Zimmermann ◽  
Vanessa C. Brambilla ◽  
Rosmary N. Brandalise ◽  
Ademir J. Zattera
Keyword(s):  
Lactic Acid ◽  
Poly Lactic Acid ◽  
Blowing Agents ◽  
Chemical Blowing Agents

Poly(lactic acid) foams reinforced with cellulose micro and nanofibers and foamed by chemical blowing agents

2017 ◽  
Vol 54 (3) ◽  
pp. 577-596 ◽  
Author(s):  
Matheus VG Zimmermann ◽  
Michelle Paola da Silva ◽  
Ademir J Zattera ◽  
Ruth MC Santana
Keyword(s):  
Lactic Acid ◽  
Expansion Method ◽  
Poly Lactic Acid ◽  
Polymeric Foams ◽  
Short Fibers ◽  
Free Expansion ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Chemical Blowing Agents ◽  
Long Fibers

Biodegradable polymeric foams have gained increasing attention as an alternative to conventional polymeric foams, whose recycling is economically unviable due to its low density. Based on this, this article discusses the development of poly(lactic acid) foams produced with the insertion of four and eight parts hundred resin (phr) of long and short cellulose fibers and nanofibers. Short fibers of nanocellulose were obtained by mechanical defibrillation and dried by lyophilization, and long fibers by CO2 supercritical fluid extraction. The poly(lactic acid) foams were produced by adding a chemical blowing agent with a pressure-free expansion method. In general, short fibers of cellulose act as nucleating agents during the expansion of the foam, which is observed by its greater number of smaller-size cells than the non-reinforced poly(lactic acid) foams. The insertion of long fibers of cellulose restricts the mobility of the polymer matrix during the expansion, thus hindering the foam its growth and formation of bubbles.

scholarly journals Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Sugar Beet ◽  
Cell Structure ◽  
Sugar Beet Pulp ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Fracture Patterns ◽  
Beet Pulp ◽  
The Impact

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.

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