scholarly journals Effects of Modified Thermoplastic Starch on Crystallization Kinetics and Barrier Properties of PLA

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4125
Author(s):  
Apoorva Kulkarni ◽  
Ramani Narayan
Keyword(s):  
Crystallization Rate ◽  
Soxhlet Extraction ◽  
Barrier Properties ◽  
Reactive Extrusion ◽  
Nucleating Agent ◽  
Thermoplastic Starch ◽  
Aqueous Environment ◽  
Screw Extruder ◽  
Avrami Analysis ◽  
Twin Screw

This study reports on using reactive extrusion (REX) modified thermoplastic starch particles as a bio-based and biodegradable nucleating agent to increase the rate of crystallization, percent crystallinity and improve oxygen barrier properties while maintaining the biodegradability of PLA. Reactive blends of maleated thermoplastic starch (MTPS) and PLA were prepared using a ZSK-30 twin-screw extruder; 80% glycerol was grafted on the starch during the preparation of MTPS as determined by soxhlet extraction with acetone. The crystallinity of PLA was found to increase from 7.7% to 28.6% with 5% MTPS. The crystallization temperature of PLA reduced from 113 °C to 103 °C. Avrami analysis of the blends showed that the crystallization rate increased 98-fold and t1/2 was reduced drastically from 20 min to <1 min with the addition of 5% MTPS compared to neat PLA. Observation from POM confirmed that the presence of MTPS in the PLA matrix significantly increased the rate of formation and density of spherulites. Oxygen and water vapor permeabilities of the solvent-casted PLA/MTPS films were reduced by 33 and 19% respectively over neat PLA without causing any detrimental impacts on the mechanical properties (α = 0.05). The addition of MTPS to PLA did not impact the biodegradation of PLA in an aqueous environment.

Characterization and Properties of Nucleated Polylactide, Poly(butylene adipate-co-terephthalate), and Thermoplastic Starch Ternary Blend Films: Effects of Compatibilizer and Starch

2013 ◽  
Vol 747 ◽  
pp. 673-677 ◽  
Author(s):  
Worasak Phetwarotai ◽  
Duangdao Aht-Ong
Keyword(s):  
Tensile Properties ◽  
Nucleating Agent ◽  
Thermoplastic Starch ◽  
Ternary Blend ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Blend Films ◽  
Flexible Polymer ◽  
Twin Screw ◽  
Thermal Stability Of

Biodegradable ternary blend films of nucleated polylactide (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and thermoplastic starch (TPS) with the presence of nucleating agent and compatibilizer were prepared via a twin screw extruder. The effects of compatibilizer types and starch contents on the thermal, morphological, and tensile properties of these blend films were evaluated. Two types of compatibilizer (methylene diphenyldiisocyanate (MDI) and polylactide-graft-maleic anhydride (PLA-g-MA)) were used for enhancing an interfacial adhesion of the blends, whereas TPS from tapioca starch was added as a filler at various concentrations (0 to 40 wt%). In addition, talc and PBAT acted as a nucleating agent and a flexible polymer were fixed at 1 phr and 10 wt%, respectively. The results indicated that the thermal stability of the blend films was affected from the presence of compatibilizer and TPS. In addition, the tensile properties and compatibility of PLA, PBAT, and TPS blends were improved with the addition of compatibilizer compared to uncompatibilized blend films as evidenced by SEM results. Furthermore, the blend films with MDI gave higher mechanical properties than those with PLA-g-MA at all compositions. The water absorption of the ternary blend films was evidently increased when the TPS amount was increased; in contrast, tensile strength and elongation at break (EB) of these blend films were significantly decreased.

scholarly journals Preparation and Properties of Thermoplastic Starch/Bentonite Nanocomposites

2017 ◽  
Vol 885 ◽  
pp. 129-134 ◽  
Author(s):  
László Lendvai ◽  
Ákos Kmetty ◽  
József Karger-Kocsis
Keyword(s):  
Thermoplastic Starch ◽  
Test Results ◽  
Maize Starch ◽  
Screw Extruder ◽  
Electron Microscopic ◽  
Sem Images ◽  
Scanning Electron Microscopic ◽  
Twin Screw ◽  
Thermal Stability Of ◽  
Scanning Electron

Thermoplastic starch (TPS)/bentonite nanocomposites containing up to 7.5 wt.% bentonite were prepared. Maize starch was plasticized with glycerol and water, in presence or absence of bentonite, in a twin-screw extruder. Mechanical, morphological and thermal properties of the TPS/bentonite nanocomposites were determined and discussed. Scanning electron microscopic (SEM) images revealed a good dispersion of bentonite particles with some remaining agglomerates in the range of 0.1 to 1.5 μm. According to the tensile test results the tensile strength and Young’s modulus increased significantly with increasing bentonite content, however, at cost of elongation. Thermogravimetric analysis (TGA) showed that the presence of bentonite exerted little to no effect on the thermal stability of TPS.

scholarly journals Investigation of the Thermal and Hydrolytic Degradation of Polylactide during Autoclave Foaming

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2624
Author(s):  
Julia Dreier ◽  
Christian Brütting ◽  
Holger Ruckdäschel ◽  
Volker Altstädt ◽  
Christian Bonten
Keyword(s):  
Thermal Degradation ◽  
Hydrolytic Degradation ◽  
Reactive Extrusion ◽  
Foaming Properties ◽  
Twin Screw Extruder ◽  
Degradation Behavior ◽  
Screw Extruder ◽  
Melt Strength ◽  
Twin Screw ◽  
Good Potential

Polylactide (PLA) is one of the most important bioplastics worldwide and thus represents a good potential substitute for bead foams made of the fossil-based Polystyrene (PS). However, foaming of PLA comes with a few challenges. One disadvantage of commercially available PLA is its low melt strength and elongation properties, which play an important role in foaming. As a polyester, PLA is also very sensitive to thermal and hydrolytic degradation. Possibilities to overcome these disadvantages can be found in literature, but improving the properties for foaming of PLA as well as the degradation behavior during foaming have not been investigated yet. In this study, reactive extrusion on a twin-screw extruder is used to modify PLA in order to increase the melt strength and to protect it against thermal degradation and hydrolysis. PLA foams are produced in an already known process from the literature and the influence of the modifiers on the properties is estimated. The results show that it is possible to enhance the foaming properties of PLA and to protect it against hydrolysis at the same time.

Crystallization Behavior of Polypropylene (PP)/ Polyethylene Terephthalate (PET) Composite Fibres

2008 ◽  
Vol 47-50 ◽  
pp. 833-836
Author(s):  
Dong Hui Liu ◽  
Xiao Juan Si ◽  
Jin Gao ◽  
Ling Ling Cao ◽  
Yi Min Wang
Keyword(s):  
Polyethylene Terephthalate ◽  
Differential Scanning Calorimeter ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Screw Extruder ◽  
Crystallization Peak ◽  
Twin Screw ◽  
Crystallization And Melting Behavior

Polypropylene (PP)/ polyethylene terephthalate (PET) composite fibres modified by PP-g-AA as a compatilizer were prepared by melt extrusion in a twin screw extruder. The crystallization and melting behavior of PP fibre and PP/PET composite fibres were investigated with differential scanning calorimeter (DSC)[1]. The results indicate that addition of PET acts as nucleating agent on the PP/PET composite fibres and increases the crystallization temperature of PP. [2,3]The crystallization peak temperature (Tp) increased first and decreased afterwards with the increase of PET, indicating that small amount of PET would promote the crystallization of PP, but excessive would reduce the crystallinity.

scholarly journals Studies On Compatibilization Of Recycled Polyethylene/Thermoplastic Starch Blends By Using Different Compatibilizer

2019 ◽  
Vol 17 (1) ◽  
pp. 557-563 ◽  
Author(s):  
Barıs Oner ◽  
Tolga Gokkurt ◽  
Ayse Aytac
Keyword(s):  
Maleic Anhydride ◽  
Thermoplastic Starch ◽  
Sem Analysis ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Recycled Polyethylene ◽  
Twin Screw ◽  
Starch Blends ◽  
Packaging Industry ◽  
Maleic Anhydride Copolymer

AbstractIn this study, the aim was to examine the effects of three different compatibilizers on the recycled polyethylene/ thermoplastic starch (r-LDPE/TPS) blends which are used in producing garbage bags. Polyethylene-Grafted-Maleic Anhydride (PEgMAH), maleic-anhydride modified ethylene propylene rubber (EPMgMAH) and ethylene maleic anhydride copolymer (PEMAH) were selected as the compatibilizers. r-LDPE/TPS blends with or without compatibilizer were prepared by using a twin screw extruder and characterized by means of mechanical, thermal, structural and morphological analyses. It was found that tensile strength values increased with the addition of PEgMAH but decreased with the addition of EPMgMAH. Elongations at break values of the r-LDPE/TPS blends were significantly improved by using PEgMAH and EPMgMAH. Tm and Tc values have slightly affected by the compatibilizer usage in the DSC analysis. In addition, the better interfacial interaction was observed for the compatibilized blend with the PEgMAH and EPMgMAH during the SEM analysis. It was concluded that PEgMAH and EPMgMAH showed mainly changed results in elongation at break values and this is the important parameter in the packaging industry.

Crystal Morphology and Thermal Properties of PA6/PP-g-MAH/POE Blends

2011 ◽  
Vol 366 ◽  
pp. 314-317
Author(s):  
Ming Tao Run ◽  
Wen Zhou ◽  
Bing Tao Xing ◽  
Meng Yao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Crystal Morphology ◽  
Crystallization Rate ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Acicular Crystal ◽  
Polarized Optical Microscopy ◽  
Twin Screw ◽  
Higher Temperature

The crystal morphology and thermal properties of the PA6/PP-g-MAH/POE blends prepared by twin-screw extruder were studied by polarized optical microscopy (POM) and differential scanning calorimetry (DSC) respectively. The results suggest that the crystal morphology of PA6 is acicular crystal while PP-g-MAH is micro-spherulites; The acicular crystals form across POE phase to PA6 phase, and the acicular crystals of PA6 in the POE phase have better regularity in dimension than those in amorphous PA6 phase. Acting as a compatibilizer, PP-g-MAH improves the miscibility of PA6 and POE, leading to the glass transition temperature of the blends decreases gradually with increasing POE contents. PA6 and PP-g-MAH can crystallize individually, and the formed PA6 crystals induced the crystallization of PP-g-MAH at higher temperature; furthermore, PP-g-MAH and POE components can increase the crystallization rate of PA6.

Graft Polymerization of L-Lactide onto Cellulose in Ionic Liquid via Twin Screw Extruder

2013 ◽  
Vol 658 ◽  
pp. 8-12
Author(s):  
Xuan Zhong ◽  
Xian Tao Tong ◽  
Mu Huo Yu ◽  
Hai Feng Li ◽  
Huan Li ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ionic Liquid ◽  
Ring Opening ◽  
Graft Polymerization ◽  
Reactive Extrusion ◽  
Extrusion Process ◽  
Twin Screw Extruder ◽  
Reaction Products ◽  
Screw Extruder ◽  
Twin Screw

A twin-screw extruder was used to carry out the ring opening graft polymerization of L-lactide onto cellulose through reactive extrusion process. Ionic liquid (1-butyl-3-methylimidazolium chloride) [Bmim]Cl and Sn(oct)2 were used as solvent and catalyst, respectively. FTIR, TGA and XRD were used to investigate the structure, thermal stability and crystalline behavior of the reaction products. The result showed a successful ring opening polymerization of L-lactide on cellulose. Furthermore, it showed a increased crystalline degree and thermal stability after being introduced the PLLA.

The Effect of Nanosilicates on the Performance of Polyethylene Terephthalate Films Prepared by Twin-Screw Extrusion

2021 ◽  
Vol 36 (4) ◽  
pp. 358-366
Author(s):  
A. Ghanbari ◽  
M.-C. Heuzey ◽  
P. J. Carreau
Keyword(s):  
Electron Microscopy ◽  
Polyethylene Terephthalate ◽  
Tensile Modulus ◽  
Barrier Properties ◽  
Nucleating Agent ◽  
Morphological Characterization ◽  
Nanocomposite Films ◽  
Silicate Layer ◽  
Twin Screw ◽  
Pet Films

Abstract Polyethylene terephthalate (PET) films were prepared by cast extrusion using a twin-screw extruder with a severe screw profile. The effect of an organically modified montmorillonite on thermal, mechanical, optical, and barrier properties of the PET films were investigated. Morphological characterization of the nanocomposite films was performed by employing wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) followed by image analysis. The results unfold a mixed morphology for the nanocomposite films with more than 95% exfoliated and intercalated silicate layer structures, depending on the screw rotation speed. The remarkable dispersion of the organoclay particles at the nano-level is discussed in terms of solubility parameter and favorable interactions between PET macromolecules and organic modifier of the nanoclay. The crystal content of the nanocomposite films and their cold and hot crystallization temperatures confirmed the role of silicate nanolayers as a heterogeneous nucleating agent. While all nanocomposite films exhibit higher haze values in comparison to the neat PET samples, incorporation of 2 wt% nanoclay brought about 25% increase in tensile modulus and barrier properties. A range of screw rotation speeds with optimized properties in terms of haze, morphology, thermal, mechanical, and barrier properties is suggested.

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