scholarly journals Biodegradation of Poly(Lactic Acid) Biocomposites under Controlled Composting Conditions and Freshwater Biotope

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Pavel Brdlík ◽  
Martin Borůvka ◽  
Luboš Běhálek ◽  
Petr Lenfeld
Keyword(s):  
Degradation Rate ◽  
Poly Lactic Acid ◽  
Screw Extruder ◽  
Flat Film ◽  
Twin Screw ◽  
Acetyl Tributyl Citrate ◽  
And Control ◽  
Aerobic Biodegradability ◽  
Qualitative Analyses

The influence of additives such as natural-based plasticiser acetyl tributyl citrate (ATBC), CaCO3 and lignin-coated cellulose nanocrystals (L-CNC) on the biodegradation of polylactic acid (PLA) biocomposites was studied by monitoring microbial metabolic activity through respirometry. Ternary biocomposites and control samples were processed by a twin-screw extruder equipped with a flat film die. Commonly available compost was used for the determination of the ultimate aerobic biodegradability of PLA biocomposites under controlled composting conditions (ISO 14855-1). In addition, the hydro-degradability of prepared films in a freshwater biotope was analysed. To determine the efficiency of hydro-degradation, qualitative analyses (SEM, DSC, TGA and FTIR) were conducted. The results showed obvious differences in the degradation rate of PLA biocomposites. The application of ATBC at 10 wt.% loading increased the biodegradation rate of PLA. The addition of 10 wt.% of CaCO3 into the plasticised PLA matrix ensured an even higher degradation rate at aerobic thermophilic composting conditions. In such samples (PLA/ATBC/CaCO3), 94% biodegradation in 60 days was observed. In contrast, neat PLA exposed to the same conditions achieved only 16% biodegradation. Slightly inhibited microorganism activity was also observed for ternary PLA biocomposites containing L-CNC (1 wt.% loading). The results of qualitative analyses of degradation in a freshwater biotope confirmed increased biodegradation potential of ternary biocomposites containing both CaCO3 and ATBC. Significant differences in the chemical and structural compositions of PLA biocomposites were found in the evaluated period of three months.

Determination of the phase structure of polymerblends by electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 492-493
Author(s):  
Dr. G. Kaemof
Keyword(s):  
Screw Extruder ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Single Screw Extruder ◽  
Transmission Electron ◽  
The Matrix ◽  
Twin Screw ◽  
Special Case ◽  
Microscopic Investigations

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.

scholarly journals Properties of Poly(Lactic Acid) Filled with Hydrophobic Cellulose/SiO2 Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kittithorn Lertphirun ◽  
Kawee Srikulkit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Hydrolysis Of Cellulose ◽  
One Step ◽  
Hydrolysis Of

Hydrophobic cellulose/SiO2 composites were prepared. Resultant hydrophobic cellulose/SiO2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190°C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO2/PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate.

Morphological, Thermal and Mechanical Properties of Poly(Lactic Acid)/Cellulose/ Nano-Clay Composite

2020 ◽  
Vol 856 ◽  
pp. 331-338
Author(s):  
Sirisart Ouajai ◽  
Suttinun Phongtamrug
Keyword(s):  
Mechanical Properties ◽  
Flexural Modulus ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Nano Clay ◽  
Twin Screw ◽  
Modified Cellulose

This research has focused on the effect of modified cellulose and clay on the thermal and mechanical properties of PLA bio-nanocomposite. Cellulose was chemically modified with silane coupling agent in order to enhance compatiblization with PLA. Successful modification was confirmed by Fourier Transform Infrared Spectroscopy and EDX-SEM. PLA was compounded with various amounts and ratios of the modified cellulose and clay by a twin-screw extruder. Thermal properties of the bio-nanocomposites were characterized by Thermogravimetric Analysis and Differential Scanning Calorimetry. Glass transition temperature of the bio-nanocomposite slightly decreased whereas melting temperature remained constant when the amount of both fillers was increased. In addition, crystallization behaviour of PLA has been influenced by the type and amount of the fillers. Clay showed a greater effect on the crystallization of PLA than the modified cellulose and unmodified one, respectively. The flexural modulus of the composite containing equal amount between clay and cellulose was increased with an increasing in fillers contents. But the flexural and impact strength of composite were gradually decreased with an increase in fillers contents. Variation of clay and cellulose ratio resulted in the change of mechanical properties. The composite containing higher ratio between clay:cellulose or cellulose:clay showed a better mechnical properties comparing to the ratio of clay:cellulose equal to 1:1.

Extrusion of An Effervescent Granulation with a Twin Screw Extruder, Baker Perkins MPF 50D. Determination of Mean Residence Time

1988 ◽  
Vol 14 (5) ◽  
pp. 649-655 ◽  
Author(s):  
N. -O. Lindberg ◽  
M. Myrenas ◽  
C. Tufvesson ◽  
L. Olbjer
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw

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.

Thermal Properties Determination of Polypropylene/Rice Straw Biocomposite Foam via DSC

2014 ◽  
Vol 695 ◽  
pp. 216-219
Author(s):  
Nazuha Tugiman ◽  
Zurina Mohamad ◽  
Wan Aizan Wan Abdul Rahman
Keyword(s):  
Thermal Properties ◽  
Rice Straw ◽  
Dicumyl Peroxide ◽  
Polymer Foam ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Blowing Agent ◽  
Foaming Process ◽  
Twin Screw

Polymer foam biocomposites based on polypropylene/rice straw (PP/RS) were successfully prepared by using an extrusion foaming process. The compounding of PP and RS was performed in a twin-screw extruder which was blended with crosslinker; dicumyl peroxide (DCP) and blowing agent; azodicarbonamide (AZ). The foam biocomposite was extruded at temperatures of 180, 190, 190 and 200 °C respectively, which set from the feeder until the die zone. The thermal properties were investigated by using differential scanning calorimetry (DSC).

scholarly journals Influence of the Conditions of Corotating Twin-Screw Extrusion for Talc-Filled Polypropylene on Selected Properties of the Extrudate

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1460 ◽  
Author(s):  
Sasimowski ◽  
Majewski ◽  
Grochowicz
Keyword(s):  
Maximum Tensile Stress ◽  
Extrusion Process ◽  
Twin Screw Extrusion ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Melt Flow Rate ◽  
Test Segment ◽  
Screw Extrusion ◽  
Twin Screw

The aim of the study was to determine the effect of the application of processing screws with a modified test segment in a corotating twin-screw extruder on selected properties of talc-filled polypropylene extrudate. The test segment was built of trilobe kneading elements and its design modifications refered to changing the distance between the kneading elements and the angle of positions of kneading elements that are relative to each other. The performed tests included the production of extrudate with various degrees of talc-filling using five design solutions of the test segment and then measurements of selected properties, such as tensile strength, elongation at maximum tensile stress, and melt flow rate. Structural studies using scanning electron microscope (SEM) and differential scanning calorimetry (DSC) were also carried out. The study includes not only the description of experimental results but also the determination of empirical models describing the dependence of the properties of the obtained extrudate on the conditions of the extrusion process and the design features of the test segment.

Co-Continuous PPS/PA66 Composites - Part II: Mechanical Performance

2013 ◽  
Vol 804 ◽  
pp. 102-105
Author(s):  
Tao Yin ◽  
Yu Qi Gu ◽  
Chun Yu Yu ◽  
Zi Xin Li
Keyword(s):  
Mechanical Properties ◽  
Phase Structure ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Continuous Phase ◽  
Polyamide 66 ◽  
Screw Extruder ◽  
Wide Range ◽  
Twin Screw

Poly (phenylene sulfide) (PPS) was blended with polyamide 66 (PA66) in a wide range of compositions by using a co-rotating twin-screw extruder. Dynamic mechanical analysis was used in determination of the co-continuous phase. The results allowed to precisely detecting the range of co-continuity. In addition, the mechanical properties of PPS/PA66 composites can also be used to identify the dispersed/matrix phase or co-continuous phase structure.

Characterization of Ceramic Batch Via Capillary Rheometry

1992 ◽  
Vol 289 ◽  
Author(s):  
Victor F. Janas ◽  
Christopher J. Malarkey ◽  
David R. Treacy ◽  
Michael E. Zak
Keyword(s):  
Wall Slip ◽  
Power Law Model ◽  
Screw Extruder ◽  
Element Analysis ◽  
Capillary Rheometry ◽  
Rheological Models ◽  
Twin Screw ◽  
Paste Viscosity

AbstractRheological testing has been developed to predict the extrudability of ceramic pastes. Inorganic batches containing cellulosic binders were mixed in a twin screw extruder prior to characterization in a capillary rheometer. Various die lengths were used to separate viscosity from wall slip parameters. A power law model was fit to the paste viscosity. The wall shear stress, assuming 100% slip, was a linear function of the wall velocity. The resulting rheological models were used in fluid flow finite element analysis for determination of extrusion pressure, and the evaluation of binders.

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