Evaluation of thermal resistance and mechanical properties of injected molded stereocomplex of poly(l -lactic acid) and poly(d -lactic acid) with various molecular weights

2017 ◽  
Vol 37 (6) ◽  
pp. 1674-1681 ◽  
Author(s):  
Yuzeng Li ◽  
Qiao Li ◽  
Gesheng Yang ◽  
Ruihao Ming ◽  
Minmin Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Resistance ◽  
Molecular Weights

Poly(lactic acid)/polypropylene and compatibilized poly(lactic acid)/polypropylene blends prepared by a vane extruder: analysis of the mechanical properties, morphology and thermal behavior

2015 ◽  
Vol 35 (8) ◽  
pp. 753-764 ◽  
Author(s):  
Rong-yuan Chen ◽  
Wei Zou ◽  
Hai-chen Zhang ◽  
Gui-zhen Zhang ◽  
Zhi-tao Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Resistance ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Crystallization Property ◽  
The Matrix ◽  
Pp Blends

Abstract Poly(lactic acid) (PLA)/polypropylene (PP) blends with different weight fractions were prepared by a novel vane extruder. The mechanical properties, morphology, crystallization behavior and thermal stability of the blends were investigated. The tensile strength, flexural strength and elongation at break decreased nonlinearly when the PP content was not more than 50 wt% and then increased with an increase in the PP content. The flexural modulus decreased with increasing PP weight fraction. The PLA/PP 90:10 blend exhibited the optimum impact strength. Scanning electron microscopy measurements revealed that the PLA/PP blends were immiscible. Phase separation occurred significantly at a blend ratio of 50:50. Regarding the PLA/PP 90:10 blend, the mean diameter of the disperse-phase PP particles was the smallest at 1.11 μm. Differential scanning calorimetry measurements showed that low content of PP enhanced the crystallization of PLA. The PLA component in the blends impeded the crystallization of PP when PP was used as the matrix. The thermogravimetric analysis measurement involved a two-step decomposition process of the blends. The thermal resistance of the blends was improved by compounding with PP. As compatibilizers, both the maleic anhydride-grafted PP and the ethylene/n-butyl acrylate/glycidyl methacrylate terpolymer helped improve the mechanical properties, crystallization property and thermal resistance of the PLA/PP blends.

Effect of Glycidyl Methacrylate (GMA) Content on Grafting Yield and Mechanical Properties of GMA Grafted Poly(Lactic Acid) Prepared by Melt Mixing Method

2016 ◽  
Vol 709 ◽  
pp. 27-31
Author(s):  
Thanh Chi Nguyen ◽  
Ruksakulpiwat Chaiwat ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Glycidyl Methacrylate ◽  
Fracture Behaviour ◽  
Industrial Applications ◽  
Proton Nuclear Magnetic Resonance ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Molecular Weights ◽  
Grafting Reaction

Glycidyl methacrylate (GMA) was grafted onto poly (lactic acid) (PLA) by internal mixer using dicumyl peroxide (DCP) as an initiator. The results from proton nuclear magnetic resonance (1H-NMR) and gel permeation chromatograph (GPC) indicated that the grafting reaction of GMA onto PLA took place successfully. In order to obtain the optimal GMA content used to graft onto PLA chain, the GMA content was varied into 5, 10 and 15 wt% of PLA. GMA content of 10 wt% was found to give the highest elongation at break of glycidyl methacrylate grafted poly (lactic acid) (PLA-g-GMA). The weight-average molecular weights, the number-average molecular weights and polydispersity index of PLA increased after grafting with GMA. After grafting, the brittle fracture behaviour of PLA was changed to ductile fracture behaviour of PLA-g-GMA. With its superior mechanical properties compared to those of pure PLA, PLA-g-GMA can be considered to be used as a new generation of biodegradable polymer, which can be applied in many industrial applications.

Click chemistry synthesis, stereocomplex formation, and enhanced thermal properties of well-defined poly(l-lactic acid)-b-poly(d-lactic acid) stereo diblock copolymers

2017 ◽  
Vol 8 (6) ◽  
pp. 1006-1016 ◽  
Author(s):  
Lili Han ◽  
Qing Xie ◽  
Jianna Bao ◽  
Guorong Shan ◽  
Yongzhong Bao ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Thermal Resistance ◽  
Click Chemistry ◽  
Diblock Copolymers ◽  
Molecular Weights ◽  
Stereocomplex Formation

PLLA-b-PDLAs with well-controlled molecular weights, compositions, highly enhanced stereocomplexation ability, and thermal resistance were synthesized by ROP and click chemistry.

Conductivity and mechanical properties of carbon black-reinforced poly(lactic acid) (PLA/CB) composites

2021 ◽  
Author(s):  
Jipeng Guo ◽  
Chi-Hui Tsou ◽  
Yongqi Yu ◽  
Chin-San Wu ◽  
Xuemei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Carbon Black ◽  
Poly Lactic Acid

scholarly journals A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 776
Author(s):  
Sixiang Zhai ◽  
Qingying Liu ◽  
Yuelong Zhao ◽  
Hui Sun ◽  
Biao Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Composite Materials ◽  
Crystallization Rate ◽  
Research Progress ◽  
Poly Lactic Acid ◽  
Green Composite ◽  
Materials Development ◽  
Research Attention ◽  
Biomass Components

With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.

scholarly journals Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Han-Seung Ko ◽  
Sangwoon Lee ◽  
Doyoung Lee ◽  
Jae Young Jho
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Flexural Strength ◽  
Interfacial Adhesion ◽  
Glycolic Acid ◽  
Compact Bone ◽  
Poly Lactic Acid ◽  
Coupling Reactions ◽  
The Poor ◽  
Human Compact Bone

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

scholarly journals Analysis of the Impact on the Mechanical Properties of Modification of Oligohydroxyethers in Organic Solvent Solution with Rubbers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski
Keyword(s):  
Mechanical Properties ◽  
Scientific Paper ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Molecular Weights ◽  
Wide Range ◽  
Strength Tests ◽  
Materials Used ◽  
Styrene Butadiene ◽  
The Impact

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.

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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