Application of Melt-Blown Poly(lactic acid) Fibres in Self-Reinforced Composites

The aim of our research was to produce poly(lactic acid) (PLA) fibres with diameters in the micrometer size range, serving as the reinforcing phase in self-reinforced (SR) PLA composites. Nonwoven PLA mats were manufactured by solvent-free melt-blowing technology. Three types of PLA differing in d-lactide content were processed with a productivity as high as 36 g/h. The crystallinity of the PLA microfibres was enhanced by thermal annealing. A 2–3-fold increase in the degree of crystallinity was obtained, as measured by differential scanning calorimetry (DSC). Fibre diameters between 2–14 µm were revealed by scanning electron microscopy (SEM). Static tensile tests were performed on the nonwoven mats, showing the reduced moduli of the annealed fibres due the amorphous relaxation. The PLA mats were processed via the hot compaction technique and formed into SR–PLA composites. The morphological and mechanical properties of the obtained microstructural composites were comprehensively studied. Composites prepared from annealed, thermally more stable PLA nonwoven mats showed superior mechanical properties; the tensile strength improved by 47% due to the higher residual fibre content.

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Influence of the Lignin Content on the Properties of Poly(Lactic Acid)/lignin-Containing Cellulose Nanofibrils Composite Films

Polymers ◽

10.3390/polym10091013 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1013 ◽

Cited By ~ 11

Author(s):

Xuan Wang ◽

Yuan Jia ◽

Zhen Liu ◽

Jiaojiao Miao

Keyword(s):

Lactic Acid ◽

Lignin Content ◽

Cellulose Nanofibrils ◽

Composite Films ◽

Tensile Tests ◽

Nucleating Agent ◽

Mechanical Analysis ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

Scanning Calorimetry

Poly(lactic acid) (PLA)/lignin-containing cellulose nanofibrils (L-CNFs) composite films with different lignin contents were produced bythe solution casting method. The effect of the lignin content on the mechanical, thermal, and crystallinity properties, and PLA/LCNFs interfacial adhesion wereinvestigated by tensile tests, thermogravimetric analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The tensile strength and modulus of the PLA/9-LCNFs (9 wt % lignin LCNFs) composites are 37% and 61% higher than those of pure PLA, respectively. The glass transition temperature (Tg) decreases from 61.2 for pure PLA to 52.6 °C for the PLA/14-LCNFs (14 wt % lignin LCNFs) composite, and the composites have higher thermal stability below 380 °C than pure PLA. The DSC results indicate that the LCNFs, containing different lignin contents, act as a nucleating agent to increase the degree of crystallinity of PLA. The effect of the LCNFs lignin content on the PLA/LCNFs compatibility/adhesion was confirmed by the FTIR, SEM, and Tg results. Increasing the LCNFs lignin content increases the storage modulus of the PLA/LCNFs composites to a maximum for the PLA/9-LCNFs composite. This study shows that the lignin content has a considerable effect on the strength and flexibility of PLA/LCNFs composites.

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Thermal Properties of Poly(Lactic Acid) Modified Poly(3-Hydroxybutyrate-co-4-Hydroxbutyrate)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.852.677 ◽

2016 ◽

Vol 852 ◽

pp. 677-685

Author(s):

Mei Li ◽

Zhi Qiang Li ◽

Wei Shao

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Thermal Properties ◽

Tensile Tests ◽

Poly Lactic Acid ◽

Flow Properties ◽

Scanning Calorimetry ◽

Melt Flow Rate ◽

Elongation At Break ◽

Good Flow

The thermal properties of poly (lactic acid)[PLA] modified poly (3 –hydroxybutyrate –co-4 -hydroxbutyrate) [P(3HB-co-4HB)], prepared by melt blending with different blending ratios were investigated by differential scanning calorimetry [DSC], thermogravimetry [TGA], melt flow rate [MFR] and tensile test measurements, and scanning electron microscopy [SEM]. The DSC tests showed that the glass transition temperature, Tg, of P(3HB-co-4HB) increased from-7°C to 56°C when mixed with 50% to 67% of PLA. A decrease in crystallization temperature, Tc, of P(3HB-co-4HB) broadened the melting interval. The MFR tests indicated the blends had good flow properties and the variation of the PLA content had little effect on the flow properties. The tensile tests showed that PLA improved the mechanical properties of P(3HB-co-4HB), including the tensile strength and elongation at break. The blends had the best mechanical properties when the percentage of PLA was 64%.

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Effects of walnut shell powders on the morphology and the thermal and mechanical properties of poly(lactic acid)

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705719828801 ◽

2019 ◽

Vol 33 (10) ◽

pp. 1383-1395

Author(s):

Hongjuan Zheng ◽

Zhengqian Sun ◽

Hongjuan Zhang

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Property Testing ◽

Walnut Shell ◽

Poly Lactic Acid ◽

Thermal And Mechanical Properties ◽

Scanning Calorimetry ◽

Elongation At Break ◽

Heat Distortion Temperature ◽

Testing Techniques

Poly(lactic acid) (PLA) has good environmental compatibility, however, its high brittleness, slow rate of crystallization, and low heat distortion temperature restrict its widespread use. To overcome these limitations, in this study, PLA was mixed with walnut shell (WS) powders. The effects of WS powders on the morphology and the thermal and mechanical properties of PLA were investigated. The products were characterized by differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarizing optical microscopy (POM), and various mechanical property testing techniques. The results showed that WS powders had a significant effect on the morphology and the thermal and mechanical properties of PLA. The tensile strength, impact strength, and elongation at break of the PLA/WS composites first increased and then decreased with the increasing addition of WS powders. When the addition of WS powders was about 0.5 wt%, they reached maximum values of 51.2 MPa, 23.3 MPa, and 19.0%, respectively. Compared with neat PLA, the spherulite grain size of the composites could be reduced and many irregular polygons were formed during crystallization. The melting, cold crystallization, and glass-transition temperatures of the composites were lower than those of neat PLA.

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Structure and properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/poly(L-lactic acid) quasi core/sheath melt-electrospun microfibers

Textile Research Journal ◽

10.1177/0040517518779997 ◽

2018 ◽

Vol 89 (9) ◽

pp. 1770-1781 ◽

Cited By ~ 1

Author(s):

Huaizhong Xu ◽

Benedict Bauer ◽

Masaki Yamamoto ◽

Hideki Yamane

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Lactic Acid ◽

Tensile Tests ◽

Processing Parameters ◽

Structure And Properties ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Diffraction Patterns

A facile route was proposed to fabricate core–sheath microfibers, and the relationships among processing parameters, crystalline structures and the mechanical properties were investigated. The compression molded poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/poly(L-lactic acid) (PLLA) strip enhanced the spinnability of PHBH and the mechanical properties of PLLA as well. The core–sheath ratio of the fibers was determined by the prefab strip, while the PLLA sheath component did not completely cover the PHBH core component due to the weak interfacial tension between the melts of PHBH and PLLA. A rotational target was applied to collect aligned fibers, which were further drawn in a water bath. The tensile strength and the modulus of as-spun and drawn fibers increased with increasing the take-up velocities. When the take-up velocity was above 500 m/min, the jet became unstable and started to break up at the tip of the Taylor cone, decreasing the mechanical properties of the fibers. The drawing process facilitated the crystallization of PLLA and PHBH, and the tensile strength and the modulus increased linearly with the increasing the draw ratio. The crystal information displayed from wide-angle X-ray diffraction patterns and differential scanning calorimetry heating curves supported the results of the tensile tests.

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Hemp Fibre Reinforced Poly(Lactic Acid) Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.29-30.337 ◽

2007 ◽

Vol 29-30 ◽

pp. 337-340 ◽

Cited By ~ 21

Author(s):

M.A. Sawpan ◽

K.L. Pickering ◽

Alan Fernyhough

Keyword(s):

Lactic Acid ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Hemp Fibre ◽

Reinforcing Material ◽

Fibre Loading ◽

The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

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Properties of poly(lactic acid-co-glycolic acid) film modified by blending with polyurethane

Chemical Papers ◽

10.2478/s11696-013-0438-1 ◽

2014 ◽

Vol 68 (2) ◽

Author(s):

Guo-Quan Zhu ◽

Fa-Gang Wang ◽

Hong-Sheng Tan ◽

Qiao-Chun Gao ◽

Yu-Ying Liu

Keyword(s):

Lactic Acid ◽

Glycolic Acid ◽

Chemical Properties ◽

Tensile Tests ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

Blend Films ◽

Surface Contact Angle ◽

Surface Morphologies ◽

And Chemical Properties

AbstractA number of poly(lactic acid-co-glycolic acid)/polyurethane (PLGA/PU) blend films with various PU mole contents were prepared by casting the polymer blend solution in chloroform. The surface morphologies of the PLGA/PU blend films were studied by scanning electron microscopy (SEM). The thermal, mechanical and chemical properties of the PLGA/PU blend films were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile tests and surface contact angle tests. The results revealed that the introduction of PU could markedly modify the properties of PLGA films.

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Crystallization and Thermal Degradation of Green Nanocomposites Based on Lignin Coated Cellulose Nanocrystals and Poly(Lactic Acid)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.737.256 ◽

2017 ◽

Vol 737 ◽

pp. 256-261 ◽

Cited By ~ 1

Author(s):

Martin Boruvka ◽

Luboš Bĕhálek

Keyword(s):

Lactic Acid ◽

Cellulose Nanocrystals ◽

Raw Material ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

Crystalline Cellulose ◽

Melt Crystallization ◽

Scanning Calorimetry ◽

Wide Range ◽

Twin Screw

Cellulose is almost inexhaustible source of raw material comprising at least one-third of all biomass matter. Through deconstruction of cellulose hierarchical structure can be extracted highly crystalline cellulose nanocrystals (CNC) with impressive properties. However, the main barrier in the processing of the nanocomposites based on CNC is their inhomogeneous dispersion and distribution in the non-polar polymer matrix. In this paper is this problem addressed by use of novel hydrophobic lignin coated CNC as a biobased nucleation agents in poly (lactic acid) (PLA) nanocomposites. These green nanocomposites based on natural plant derived substances have enormous potential to replace materials originated from non-renewable resources and show promise of providing degradation back into the environment when they are no longer needed. Resulted composites prepared by twin screw extrusion and injection moulding were characterized by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of L-CNC (1, 2 and 3 wt. %) into PLA increased melt crystallization enthalpy and decreases the cold crystallization enthalpy. The degree of crystallinity (cc) increased from 5.6 % (virgin PLA) to 8.5 % (PLA/1-L-CNC), 10.3 % (PLA/2-L-CNC) and 10.7 % (PLA/3-L-CNC). The wide range of degradation temperatures of lignin coating has been observed starting at 100 °C.

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Crystallization Kinetics of Poly(lactic acid)–Graphene Nanoscroll Nanocomposites: Role of Tubular, Planar, and Scrolled Carbon Nanoparticles

C – Journal of Carbon Research ◽

10.3390/c7040075 ◽

2021 ◽

Vol 7 (4) ◽

pp. 75

Author(s):

Oluwakemi Ajala ◽

Caroline Werther ◽

Rauf Mahmudzade ◽

Peyman Nikaeen ◽

Dilip Depan

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Crystallization Kinetics ◽

Crystallization Rate ◽

Melting Behavior ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

Avrami Model ◽

Superior Mechanical Properties ◽

Kinetics Of

Graphene nanoscrolls (GNS) are 1D carbon-based nanoparticles. In this study, they were investigated as a heterogeneous nucleating agent in the poly(lactic acid) (PLA) matrix. The isothermal and non-isothermal melting behavior and crystallization kinetics of PLA-GNS nanocomposites were investigated using a differential scanning calorimeter (DSC). Low GNS content not only accelerated the crystallization rate, but also the degree of crystallinity of PLA. The Avrami model was used to fit raw experimental data, and to evaluate the crystallization kinetics for both isothermal and non-isothermal runs through the nucleation and growth rate. Additionally, the effect of the dimensionality and structure of the nanoparticle on the crystallization behavior and kinetics of PLA is discussed. GNS, having a similar fundamental unit as CNT and GNP, were observed to possess superior mechanical properties when analyzed by the nanoindentation technique. The scrolled architecture of GNS facilitated a better interface and increased energy absorption with PLA compared to CNTs and GNPs, resulting in superior mechanical properties.

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Barrier Properties and Hydrophobicity of Biodegradable Poly(lactic acid) Composites Reinforced with Recycled Chinese Spirits Distiller’s Grains

Polymers ◽

10.3390/polym13172861 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2861

Author(s):

Zhi-Jun Chen ◽

Chi-Hui Tsou ◽

Meng-Lin Tsai ◽

Jipeng Guo ◽

Manuel Reyes De Guzman ◽

...

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Barrier Properties ◽

Poly Lactic Acid ◽

Control Group ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Distiller's Grains ◽

The Matrix ◽

Section Structure

Adding natural biomass to poly(lactic acid) (PLA) as a reinforcing filler is a way to change the properties of PLA. This paper is about preparing PLA/biomass composites by physically melting and blending Chinese Spirits distiller’s grains (CSDG) biomass and PLA to optimize the composite performance. Composites of modified PLA (MPLA) with varying amounts of CSDG were also prepared by the melt-mixing method, and unmodified PLA/CSDG composites were used as a control group for comparative analysis. The functional groups of MPLA enhanced the compatibility between the polymer substrate and CSDG. The composite water vapor/oxygen barrier and mechanical properties were studied. It was found that the barrier and mechanical properties of MPLA/CSDG composites were significantly improved. SEM was adopted to examine the tensile section structure of the composites, and the compatibility between the filler and the matrix was analyzed. An appropriate amount of CSDG had a better dispersibility in the matrix, and it further improved the interfacial bonding force, which in turn improved the composite mechanical properties. X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were conducted to determine the crystalline properties and to analyze the stability of the composites. It was found that the CSDG content had a significant effect on the crystallinity. Barrier and biodegradation mechanisms were also discussed.

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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

Journal of Polymer Engineering ◽

10.1515/polyeng-2014-0312 ◽

2015 ◽

Vol 35 (8) ◽

pp. 753-764 ◽

Cited By ~ 3

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.

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