scholarly journals Grafted Lactic Acid Oligomers on Lignocellulosic Filler towards Biocomposites

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 314
Author(s):  
Anna Czajka ◽  
Radosław Bulski ◽  
Anna Iuliano ◽  
Andrzej Plichta ◽  
Kamila Mizera ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Testing Machine ◽  
Thermal Characteristics ◽  
Poly Lactic Acid ◽  
Glass Temperature ◽  
Sem Images ◽  
Tensile Testing Machine ◽  
Filler Particles ◽  
Lignocellulosic Filler

Lactic acid oligomers (OLAs) were in situ synthesized from lactic acid (LAc) and grafted onto chokeberry pomace (CP) particleboards by direct condensation. Biocomposites of poly (lactic acid) (PLA) and modified/unmodified CP particles containing different size fractions were obtained using a mini-extruder. To confirm the results of the grafting process, the FTIR spectra of filler particles were obtained. Performing 1HNMR spectroscopy allowed us to determine the chemical structure of synthesized OLAs. The thermal degradation of modified CP and biocomposites were studied using TGA, and the thermal characteristics of biocomposites were investigated using DSC. In order to analyse the adhesion between filler particles and PLA in biocomposites, SEM images of brittle fracture surfaces were registered. The mechanical properties of biocomposites were studied using a tensile testing machine. FTIR and 1HNMR analysis confirmed the successful grafting process of OLAs. The modified filler particles exhibited a better connection with hydrophobic PLA matrix alongside improved mechanical properties than the biocomposites with unmodified filler particles. Moreover, a DSC analysis of the biocomposites with modified CP showed a reduction in glass temperature on average by 9 °C compared to neat PLA. It confirms the plasticizing effect of grafted and ungrafted OLAs. The results are promising, and can contribute to increasing the use of agri-food lignocellulosic residue in manufacturing biodegradable packaging.

scholarly journals Effect of a Novel Flame Retardant on the Mechanical, Thermal and Combustion Properties of Poly(Lactic Acid)

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2407
Author(s):  
Mingjun Niu ◽  
Zhongzhou Zhang ◽  
Zizhen Wei ◽  
Wanjie Wang
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Flame Retardant ◽  
Testing Machine ◽  
Poly Lactic Acid ◽  
Limiting Oxygen Index ◽  
Biobased Materials ◽  
Cone Calorimeter Test ◽  
Combustion Properties ◽  
Ul 94

Poly(lactic) acid (PLA) is one of the most promising biobased materials, but its inherent flammability limits its applications. A novel flame retardant hexa-(DOPO-hydroxymethylphenoxy-dihydroxybiphenyl)-cyclotriphosphazene (HABP-DOPO) for PLA was prepared by bonding 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) to cyclotriphosphazene. The morphologies, mechanical properties, thermal stability and burning behaviors of PLA/HABP-DOPO blends were investigated using a scanning electron microscope (SEM), a universal mechanical testing machine, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), vertical burning (UL-94) and a cone calorimeter test (CCT). The LOI value reached 28.5% and UL-94 could pass V-0 for the PLA blend containing 25 wt% HABP-DOPO. A significant improvement in fire retardant performance was observed for PLA/HABP-DOPO blends. PLA/HABP-DOPO blends exhibited balanced mechanical properties. The flame retardant mechanism of PLA/HABP-DOPO blends was evaluated.

Studies on Processing Rheological and Mechanical Properties of Poly(lactic acid)/Sesbania Gum/Nano-silica Composites

2017 ◽  
Vol 25 (5) ◽  
pp. 395-404
Author(s):  
Qing Zhang
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Rheological Properties ◽  
Testing Machine ◽  
Silica Content ◽  
Impact Testing ◽  
Poly Lactic Acid ◽  
Nano Silica ◽  
Bending Tests ◽  
Sesbania Gum

Processing rheological properties of poly(lactic acid) (PLA)/sesbania gum (SG)/nano-silica composites were investigated with a torque rheometer, and mechanical properties were researched by a universal testing machine and a cantilever-beam impact testing machine. Effects of SG content, nano-silica content, the types of plasticisers, the plasticiser content and the rotor speed of a torque rheometer on the properties of composites were discussed. The results indicated that polyethylene glycol (PEG)20000 exhibited the best plasticising effect on the composites, and at the same time, did not increase energy consumption of the systems compared with other four plasticisers. As for the aspect of processing rheological properties, the optimum formulation for PLA/SG/ nano-SiO2/PEG20000 composites was: 100 parts of PLA, 8 parts of SG, 2 parts of nano-SiO2, and 5–10 parts of PEG20000. Comparing with unmodified PLA, the comprehensive mechanical properties of the composites improved greatly, based on the results of the tensile, impact and bending tests.

Preparation and Properties of Cotton Fiber/Poly(lactic acid) Composites

2014 ◽  
Vol 789 ◽  
pp. 100-105 ◽  
Author(s):  
Jin Qian ◽  
Min Min Yu ◽  
Zhao Ge ◽  
Ming Jie Xu ◽  
Hui Hui Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Coupling Agent ◽  
Cotton Fiber ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Fiber Content ◽  
Poly Lactic Acid ◽  
Interface Morphology

In order to improve the mechanical properties of poly (lactic acid) (PLA), cotton fiber/PLA composites were prepared by melting compounding and injection molding. The effects of cotton fiber content and coupling agent on mechanical properties, crystalline behavior and interface morphology of the composites were studied by universal testing machine, DSC and SEM, respectively. The results showed that the crystallinity of the composites increased gradually with the increase of cotton fiber content, whereas the mechanical properties of the composites increased firstly and then decreased with further addition of cotter fiber. The composite with 20wt% cotton fiber had an optimal mechanical performance. In addition, with the incorporation of 1wt% coupling agent, the interfacial adhesion between cotton fiber and PLA improved obviously, and the mechanical properties of the composites increased accordingly. Compared with the neat PLA, the tensile strength, flexural strength, flexural modulus and impact strength of the resultant composites were increased by 66.0%, 27.4%, 45.8% and 60.4%, respectively.

Effect of Surface Treatment on Interfacial and Properties of Water Hyacinth Fiber Reinforced Poly(Lactic Acid) Composites

2012 ◽  
Vol 463-464 ◽  
pp. 449-452
Author(s):  
Achanai Buasri ◽  
Nattawut Chaiyut ◽  
Teerut Petsungwan ◽  
Yutthakarn Boonyuen ◽  
Sansana Moonmanee
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Surface Treatment ◽  
Water Hyacinth ◽  
Testing Machine ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Weight Content ◽  
Uniform Dispersion ◽  
Water Hyacinth Fiber

Surface treatment of water hyacinth fiber (WHF) was investigated as a mean of improving interfacial of WHF reinforced poly (lactic acid) (PLA) composites. Fiber was treated with sodium hydroxide 15% w/v at 85 °C for 3 h. The composite materials were processed using internal melt mixer and compression molding machine. The weight content of fibervaried from 5 to 25% w/w.The mechanical and thermal properties of pure PLA and composites were compared using universal testing machine, differential scanning calorimetry (DSC) and thermogravimetricanalysis (TGA).The best mechanical properties of composite were achieved at fiber mass content of 20% w/w in this study, which showed an increase oftensile modulus by 21.6% compared to those of pure PLA. The high tensile modulus but low elongation at break indicates that this material exhibits brittle behavior. The results of TGA andDSC experiments indicated that the addition of fiber enhanced the thermal stability of the composites and WHF can act as a nucleating agent for PLA crystallites. The morphology, evaluated by scanning electron microscopy (SEM), indicated that a uniform dispersion of fiber in the PLA matrix existed. Alkali treatment of fiber increased the interfacial bonding strength and the wettability of the fiber by PLA leading to the enhancement in mechanical properties of the composites.

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 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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