Effect of L-lactic acid oligomer (OLLA) to cassava starch ratio on characteristics and mechanical properties of blend film

Poly(lactic acid), PLA, is a biodegradable polymer, but its applications are limited by its high cost and relatively poorer properties when compared to petroleum-based plastics. The addition of starch powder into PLA is one of the most promising efforts because starch is an abundant and cheap biopolymer. However, the challenge is the major problem associated with poor interfacial adhesion between the hydrophilic starch granules and the hydrophobic PLA, leading to poorer mechanical properties. In this paper, soybean oil maleate (SOMA) was synthesized by grafting soybean oil with various weight percents of maleic anhydride (MA) using dicumyl peroxide (DCP) as an initiator. Then, SOMA was employed for the surface modifying of cassava starch powder, resulting in SOMA-g-STARCH. The obtained SOMA-g-STARCH was mixed with PLA in various weight ratios using twin-screw extruder, resulting in PLA/SOMA-g-STARCH. Finally, the obtained PLA/SOMA-g-STARCH composites were prepared by a compression molding machines. The compatibility, thermal properties, morphology properties, and mechanical properties were characterized and evaluated. The results showed that the compatibility, surface appearance, and mechanical properties at 90 : 10 and 80 : 20 ratios of PLA/SOMA-g-STARCH were the best.

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

Iranian Polymer Journal ◽

10.1007/s13726-021-00973-2 ◽

2021 ◽

Cited By ~ 1

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

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

Polymers ◽

10.3390/polym13050776 ◽

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.

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

Nanomaterials ◽

10.3390/nano11010249 ◽

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.

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Study of mechanical properties behaviour of biodegradable blends based on wood adhesive, lactic acid, polyvinyl alcohol, and aloe Vera

Materials Today Proceedings ◽

10.1016/j.matpr.2020.12.297 ◽

2021 ◽

Author(s):

Zainab J. Sweah ◽

Mohammed Ali jaber ◽

Ahmed J. Mohammed

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Polyvinyl Alcohol ◽

Aloe Vera ◽

Wood Adhesive ◽

Biodegradable Blends

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

Polymers ◽

10.3390/polym13111851 ◽

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.

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Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽

10.3390/polym13152531 ◽

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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