scholarly journals Thermal and Mechanical Properties of Biodegradable Star-Shaped/Linear Polylactide Stereocomplexes

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Onanong Cheerarot ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Solvent Casting ◽  
Thermal And Mechanical Properties ◽  
Casting Method ◽  
Blend Ratio ◽  
Blend Films ◽  
Molecular Weights ◽  
Linear Poly ◽  
Blend Ratios

The 6-arm star-shaped poly(L-lactide) (6PLL)/linear poly(D-lactide) (1PDL) stereocomplex films were prepared by the solvent casting method. The influences of the 6PLL/1PDL blend ratios (75/25, 50/50, and 25/75 w/w) and 1PDL molecular weights (15,000, 30,000, and 60,000 g/mol) on the thermal and mechanical properties of the stereocomplex films were investigated. The 6PLL and 1PDLs had a single melting temperature (Tm) of homocrystallites at 174°C and 167°C, respectively. The 6PLL/1PDL blends had twoTms: a lowerTmof homocrystallites (160–173°C) and a higherTmof stereocomplex crystallites (219–228°C). The stereocomplex crystallinity and mechanical properties of the 6PLL/1PDL blend films were higher than those of 6PLL and 1PDL and were the highest in the 50/50 (w/w) blend ratio. However, the stereocomplex crystallinity of the 50/50 (w/w) 6PLL/1PDL blend films decreased and the mechanical properties increased as the molecular weight of 1PDL increased.

Thermal and Mechanical Properties of PLA/BN/BR Ternary Composite Films

2016 ◽  
Vol 707 ◽  
pp. 3-7
Author(s):  
Arper Baethu ◽  
Jantrawan Pumchusak
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Properties ◽  
Composite Films ◽  
Solvent Casting ◽  
Thermal And Mechanical Properties ◽  
Casting Method ◽  
Ternary Composite ◽  
Scanning Electron

In this research, the effects of boron nitride (BN) and polybutadiene (BR) on thermal and mechanical properties of polylactic acid (PLA) composite films were studied. PLA thin film in the thickness of less than 0.2 mm was fabricated using the solvent casting method. The loadings of BN and BR of 0-7 wt% were applied to the PLA matrix. The morphologies of composite films were characterized by scanning electron microscopy (SEM). The thermal and mechanical properties were also investigated. It was found that the addition of BN and BR can improve the thermal properties of PLA composite films. PLA/BN3%/BR5% ternary composite films provided the higher thermal properties, tensile strength and Young’s modulus, compared to PLA/BN1%/BR5% ternary composite films.

scholarly journals The Effect of Stereocomplex Polylactide Particles on the Stereocomplexation of High Molecular Weight Polylactide Blends

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2018
Author(s):  
Muhammad Samsuri ◽  
Ihsan Iswaldi ◽  
Purba Purnama
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Nucleating Agent ◽  
Solution Casting ◽  
Casting Method ◽  
Crystalline Fraction ◽  
Crystalline Structures ◽  
Solution Casting Method

Stereocomplexation is one of several approaches for improving polylactide (PLA) properties. The high molecular weight of poly L-lactide (PLLA) and poly D-lactide (PDLA) homopolymers are a constraint during the formation of stereocomplex PLAs (s-PLAs). The presence of s-PLA particles in PLA PLLA/PDLA blends can initiate the formation of s-PLA crystalline structures. We used the solution casting method to study the utilization of s-PLA materials from high molecular weight PLLA/PDLA blends for increasing s-PLA formation. The s-PLA particles initiated the formation of high molecular weight PLLA/PDLA blends, obtaining 49.13% s-PLA and 44.34% of the total crystalline fraction. In addition, the mechanical properties were enhanced through s-PLA crystalline formation and the increasing of total crystallinity of the PLLA/PDLA blends. The s-PLA particles supported initiation for s-PLA formation and acted as a nucleating agent for PLA homopolymers. These unique characteristics of s-PLA particles show potential to overcome the molecular weight limitation for stereocomplexation of PLLA/PDLA blends.

Synthesis of Cyclic Polysulfides and their Properties as Curing Agents

2004 ◽  
Vol 77 (2) ◽  
pp. 380-390
Author(s):  
Wonmun Choi ◽  
Tomoyuki Matsumura
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
High Molecular Weight ◽  
Mass Spectra ◽  
Elongation At Break ◽  
Molecular Weights ◽  
Aging Properties ◽  
Curing Agents ◽  
Polysulfide Polymer

Abstract The reactions of dichloroalkanes and sodium tetra-sulfide (Na2S4) were carried out in a mixture of water and toluene to produce corresponding cyclic polysulfides and polysulfide polymer. The low molecular weights of cyclic sulfides were obtained by the reaction at 90 °C, while the high molecular weight of polysulfide polymer was obtained by the reaction at 50 °C. GPC chromatograms and Mass spectra revealed that the structures of cyclic polysulfide were 1:1, 2:2, and 3:3 adducts of dichloroalkane and sodium tetra-sulfide. The mechanical properties of vulcanized NR at 148 °C with cyclic sulfides were similar to that with sulfur. However, both tensile strength and elongation at break of vulcanized NR at 170 °C with cyclic sulfides are much higher than that with sulfur. The aging properties of vulcanized NR at 148 °C or 170 °C with cyclic polysulfides indicate better stability.

scholarly journals Structures, Optical and Mechanical Properties of PLA/ZnO SiO2 Al2O3 Composite Elaborated by a Solvent Casting Method

Proceedings ◽  
2019 ◽  
Vol 26 (1) ◽  
pp. 18
Author(s):  
Bouamer ◽  
Benrekaa ◽  
Younes
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Al2o3 Composite ◽  
Optical And Mechanical Properties

In this study, granulated polylactic acid and ZnO, SiO2 and Al2O3 powders were mixed to form PLA/ZnO and PLA/ZnO SiO2 Al2O3 composites with different concentrations using a solvent casting method. [...]

Weldability of pipe grade polyethylenes as realized from thermal and mechanical properties assessments

2016 ◽  
Vol 36 (8) ◽  
pp. 853-860 ◽  
Author(s):  
Vahabodin Goodarzi ◽  
Zahed Ahmadi ◽  
Mohammad Reza Saeb ◽  
Farkhondeh Hemmati ◽  
Mehdi Ghaffari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Molecular Weight ◽  
Aging Process ◽  
Pipe Production ◽  
Lamellar Thickness ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Injection Molded ◽  
The One

Abstract Since polyethylene (PE) has been widely accepted for the production of high-pressure fluid conveying pipelines, studies devoted to weldability of PE connections were always of major importance. In this study, two industrial PE grades designed for pipe production, namely PE80 and PE100, were injection molded, cut, and then welded as PE100-PE100, PE100-PE80, and PE80-PE80. The heat-welded joints were assessed by differential scanning calorimetry and tensile measurements. The results obtained from thermal and mechanical analyses were compared with equivalents for aged samples. Thermal analysis revealed that the melting point of the PE100-PE100 sample is obviously larger than the one for the PE80-PE80 joint, for the PE80 chains deteriorate the crystallization of PE100. Further, the PE80-PE80 sample showed the lowest lamellar thickness and crystalline molecular weight among the studied joints. The aging process was found to increase lamellar thickness and molecular weight, though in the PE100-PE100 sample such quantities very limitedly increased. The yield stress of aged joints was higher than that for just-prepared samples, while an inverse trend was seen for strain at break. From a practical viewpoint, the PE100-PE100 welds offer better properties.

Silk Fibroin/Hyaluronic Acid Blend Film with Good Water Stability and Cytocompatibility

2013 ◽  
Vol 377 ◽  
pp. 209-214
Author(s):  
Ling Shuang Wang ◽  
Shu Qin Yan ◽  
Ming Zhong Li
Keyword(s):  
Cell Proliferation ◽  
Hyaluronic Acid ◽  
Silk Fibroin ◽  
Biomedical Applications ◽  
Water Resistance ◽  
High Water ◽  
Casting Method ◽  
Blend Ratio ◽  
Blend Films

Stimulating cell proliferation is a challenge in the field of silk fibroin-based biomaterials. In this study, silk fibroin/hyaluronic acid blend films were prepared by a casting method using carbodiimide as a cross-linking agent. Carbodiimide induced silk fibroin to form Silk I crystal structure which was not affected by the presence of hyaluronic acid. The films showed high water resistance. In vitro, the performance of these films was assessed by seeding L929 cells. The results indicated that the silk fibroin/hyaluronic acid blend films with the blend ratio of 80/20 and 60/40 promoted cell proliferation compared with the pure silk fibroin or hyaluronic acid film. These results suggest that silk fibroin/hyaluronic acid blend films are water stable and cytocompatible materials which are expected to be useful in biomedical applications.

Sign in / Sign up

Export Citation Format

Share Document