Amorphous fraction controlled mechanical and optical properties of polylactic acid below glass transition temperature

2020 ◽  
Vol 91 ◽  
pp. 106731
Author(s):  
Tsung-Han Yu ◽  
Yu-Hsun Su ◽  
Hsuan-Hao Huang ◽  
Hsin-Jung Tsai ◽  
Wen-Kuang Hsu
Keyword(s):  
Optical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Amorphous Fraction

The Effect of Methylene Diphenyl Diisocyanate on the Nonisothermal Properties of Polylactic Acid/Elaeis guineensis Fibres Biocomposites

2013 ◽  
Vol 594-595 ◽  
pp. 823-827
Author(s):  
Luqman Hakim Ahmad Subri ◽  
Sakinah Mohd Alauddin ◽  
Senawi Rosman
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Elaeis Guineensis ◽  
Fibre Surface ◽  
Degree Of Crystallinity ◽  
Chain Mobility ◽  
Methylene Diphenyl Diisocyanate ◽  
The Degree Of Crystallinity

Biocomposites demands are significantly rising due to environmental regulations and concerns. However, incompatibility between the fibre and matrix is a major setback that diminishes the biocompostie properties. Therefore in this work, methylene diphenyl diisocynate (MDI) compatibilizers were used together with fibre surface treatment in order to increase compatibility between polylactic acid (PLA) and Elaeis Guineensis Fibres (EGF) biocomposite. Nonisothermal properties were investigated and it was found that, MDI increased compatibility of the PLA and EGF which led to the restriction of chain movements in the biocomposite. This restriction in chain mobility caused an increase the glass transition temperature and crystallization temperature and also reduced the degree of crystallinity.

Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

2013 ◽  
Vol 130 (2) ◽  
pp. 1148-1157 ◽  
Author(s):  
Marion Dasriaux ◽  
Sylvie Castagnet ◽  
Ludovic Thilly ◽  
Laurence Chocinski-Arnault ◽  
Séverine A. E. Boyer
Keyword(s):  
High Pressure ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Amorphous Fraction

scholarly journals Preparation and Characterization of Bletilla striata Polysaccharide/Polylactic Acid Composite

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2104
Author(s):  
Renyu Yang ◽  
Dongyue Wang ◽  
Hongli Li ◽  
Yi He ◽  
Xiangyu Zheng ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Composite Film ◽  
Polylactic Acid ◽  
Tensile Tests ◽  
High Price ◽  
Film Material ◽  
Bletilla Striata ◽  
Good Thermal Stability

Polylactic acid (PLA) is limited in its application due to its high price, high brittleness and low glass-transition temperature. Modification methods are currently used to overcome these shortcomings. In this study, Bletilla striata polysaccharide (BSP) was blended with PLA by a solvent method. DMA data showed that the BSP/PLA film had a higher glass-transition temperature, and the glass-transition temperature of the film showed an extreme value of 68 °C when the proportion of the chalk polysaccharide was 0.8%. TG data indicates that the composite film material has good thermal stability. Tensile tests show that the composite film is improved in rigidity and elasticity compared to the pure PLA film. The blending modification of PLA with white peony polysaccharide not only reduces the cost of PLA, but also improves the thermal and mechanical properties of PLA.

scholarly journals Thermal Insulation and Mechanical Properties of Polylactic Acid (PLA) at Different Processing Conditions

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2091
Author(s):  
Mohamed Saeed Barkhad ◽  
Basim Abu-Jdayil ◽  
Abdel Hamid I. Mourad ◽  
Muhammad Z. Iqbal
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Thermal Insulation ◽  
Annealing Time ◽  
Insulation Material ◽  
Thermal Insulation Material

This work aims to provide an extensive evaluation on the use of polylactic acid (PLA) as a green, biodegradable thermal insulation material. The PLA was processed by melt extrusion followed by compression molding and then subjected to different annealing conditions. Afterwards, the thermal insulation properties and structural capacity of the PLA were characterized. Increasing the annealing time of PLA in the range of 0–24 h led to a considerable increase in the degree of crystallization, which had a direct impact on the thermal conductivity, density, and glass transition temperature. The thermal conductivity of PLA increased from 0.0643 W/(m·K) for quickly-cooled samples to 0.0904 W/(m·K) for the samples annealed for 24 h, while the glass transition temperature increased by approximately 11.33% to reach 59.0 °C. Moreover, the annealing process substantially improved the compressive strength and rigidity of the PLA and reduced its ductility. The results revealed that annealing PLA for 1–3 h at 90 °C produces an optimum thermal insulation material. The low thermal conductivity (0.0798–0.0865 W/(m·K)), low density (~1233 kg/m3), very low water retention (<0.19%) and high compressive strength (97.2–98.7 MPa) in this annealing time range are very promising to introduce PLA as a green insulation material.

Thermal and Optical Properties of High Refractive Index xNb2O5-(1-x)La2O3 Glasses Prepared by Aerodynamic Levitation Method

2013 ◽  
Vol 749 ◽  
pp. 255-259 ◽  
Author(s):  
Yu Xing Cheng ◽  
Gui Sheng Xu ◽  
Jian Ding Yu ◽  
Xiu Hong Pan ◽  
Ming Hui Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
High Refractive Index ◽  
Infrared Region ◽  
Crystallization Peak ◽  
Promising Application ◽  
Aerodynamic Levitation

Bulk glasses of xNb2O5(1-x)La2O3(NL) with high refractive index were prepared by aerodynamic levitation method. Only when x ranges from 0.62 to 0.72, NL glasses can be obtained. The effect of compositions on the thermal property and refractive index was investigated. The results indicated that the glass transition temperature ranged from 733 to 767 with the increasing of La2O3in NL glasses, while the crystallization peak ranged from 811 to 837 . The glasses had high refractive index ranging from 2.26 to 2.31. According to the Drude-Voigt relationship, the Abbe number of the glasses was calculated to be about 20. This type of glass was colorless and transparent in the region from visible to infrared region. Thus, the niobate glass system has promising application in lenses, next-generation optical disk, and endoscopes.

Synthesis of biorenewable and water-degradable polylactam esters from itaconic acid

2016 ◽  
Vol 18 (15) ◽  
pp. 4170-4175 ◽  
Author(s):  
Pengxu Qi ◽  
Hsiao-Li Chen ◽  
Ha Thi Hoang Nguyen ◽  
Chu-Chieh Lin ◽  
Stephen A. Miller
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Itaconic Acid ◽  
Main Chain ◽  
Lactam Ring ◽  
One Year ◽  
Chain Ester

Polylactam esters are readily made from biobased itaconic acid and are compared to polylactic acid. The lactam ring improves the glass transition temperature and the main-chain ester groups are more readily hydrolyzed, degrading fully via agitation in water for one year.

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