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

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%.

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

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.

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

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 766 ◽  
Author(s):  
Dániel Vadas ◽  
Dávid Kmetykó ◽  
György Marosi ◽  
Katalin Bocz
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Fold Increase ◽  
Tensile Tests ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Static Tensile ◽  
Micrometer Size ◽  
Nonwoven Mats

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.

Influence of extrusion screw speed on the properties of halloysite nanotube impregnated polylactic acid nanocomposites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chaitra Venkatesh ◽  
Yuanyuan Chen ◽  
Zhi Cao ◽  
Shane Brennan ◽  
Ian Major ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Composite Films ◽  
Polymer Melt ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Screw Speed ◽  
Halloysite Nanotube ◽  
The Past

Abstract Poly (lactic acid)/halloysite nanotube (PLA/HNT) nanocomposites have been studied extensively over the past few years owing to the interesting properties of the polymer, PLA, and the nanoclay, HNT, individually and as composites. In this paper, the influence of the screw speed during extrusion was investigated and was found to have a significant impact on the mechanical and thermal performance of the extruded PLA/HNT nanocomposites. To determine the effect of screw speed on PLA/HNT nanocomposites, 5 and 10 wt% of HNTs were blended into the PLA matrix through compounding at screw speeds of 40, 80, and 140 rpm. Virgin PLA was compounded for comparison. The resultant polymer melt was quench cooled onto a calendar system to produce composite films which were assessed for mechanical, thermal, chemical, and surface properties. Results illustrate that in comparison to 40 and 80 rpm, the virgin PLA when compounded at 140 rpm, indicated a significant increase in the mechanical properties. The PLA/HNT 5 wt% nanocomposite compounded at 140 rpm showed significant improvement in the dispersion of HNTs in the PLA matrix which in turn enhanced the mechanical and thermal properties. This can be attributed to the increased melt shear at higher screw speeds.

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

2018 ◽  
Vol 89 (9) ◽  
pp. 1770-1781 ◽  
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.

scholarly journals Effect of Selected Commercial Plasticizers on Mechanical, Thermal, and Morphological Properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer Biodegradable Blends for Three-Dimensional (3D) Print

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1893 ◽  
Author(s):  
Přemysl Menčík ◽  
Radek Přikryl ◽  
Ivana Stehnová ◽  
Veronika Melčová ◽  
Soňa Kontárová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Modulated Differential Scanning Calorimetry ◽  
3D Print ◽  
3D Printed ◽  
Biodegradable Blends

This paper explores the influence of selected commercial plasticizers structure, which are based on esters of citric acid, on mechanical and thermal properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer biodegradable blends. These plasticizers were first tested with respect to their miscibility with Poly(3-hydroxybutyrate)/Poly(lactic acid) (PHB/PLA) blends using a kneading machine. PHB/PLA/plasticizer blends in the weight ratio (wt %) of 60/25/15 were then prepared by single screw and corotating meshing twin screw extruders in the form of filament for further three-dimensional (3D) printing. Mechanical, thermal properties, and shape stability (warping effect) of 3D printed products can be improved just by the addition of appropriate plasticizer to polymeric blend. The goal was to create new types of eco-friendly PHB/PLA/plasticizers blends and to highly improve the poor mechanical properties of neat PHB/PLA blends (with majority of PHB) by adding appropriate plasticizer. Mechanical properties of plasticized blends were then determined by the tensile test of 3D printed test samples (dogbones), as well as filaments. Measured elongation at break rapidly enhanced from 21% for neat non-plasticized PHB/PLA blends (reference) to 328% for best plasticized blends in the form of filament, and from 5% (reference) to 187% for plasticized blends in the form of printed dogbones. The plasticizing effect on blends was confirmed by Modulated Differential Scanning Calorimetry. The study of morphology was performed by the Scanning Electron Microscopy. Significant problem of plasticized blends used to be also plasticizer migration, therefore the diffusion of plasticizers from the blends after 15 days of exposition to 110 °C in the drying oven was investigated as their measured weight loss. Almost all of the used plasticizers showed meaningful positive softening effects, but the diffusion of plasticizers at 110 °C exposition was quite extensive. The determination of the degree of disintegration of selected plasticized blend when exposed to a laboratory-scale composting environment was executed to roughly check the “biodegradability”.

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

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.

RETRACTED: Fabrication of Poly(Lactic Acid) Nanofibers by Cotton Candy Method

2017 ◽  
Vol 728 ◽  
pp. 193-198
Author(s):  
Rutchaneekorn Wongpajan ◽  
Supaphorn Thumsorn ◽  
Hiroyuki Inoya ◽  
Masayuki Okoshi ◽  
Hiroyuki Hamada
Keyword(s):  
Differential Scanning Calorimetry ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Electron Microscope ◽  
Air Pressure ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Cotton Candy ◽  
Nozzle Temperature ◽  
Scanning Electron

The poly (lactic acid) (PLA) fiber of biodegradable polymer was fabricated by cotton candy method with small nozzle. The air pressure was varied from 0.2-0.5 MPa with nozzle temperature of 210-260°C. The morphology of fiber was determined by scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). SEM results suggested that diameters the PLA fiber at temperature 250°C and air pressure of 0.2 MPa were smaller than the fiber at low and high temperature. The sizes of the fibers were lower than 1 μm and the fibers were irregular size. Crystallinity significantly decreased when increasing barrel temperatures while it slightly changed when varied air pressure. The productivity of PLA fibers was around 30-180 g/h depended on controlled the nozzle temperature and the air pressure.

Crystallization behavior and mechanical properties of poly(lactic acid) complex fiber toughened by carbon nanotube nanocapsules

2017 ◽  
Vol 88 (14) ◽  
pp. 1616-1627 ◽  
Author(s):  
Shu-qiang Liu ◽  
Gai-hong Wu ◽  
Yun-chao Xiao ◽  
Hong-xia Guo ◽  
Fen-juan Shao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Carbon Nanotube ◽  
Crystallization Behavior ◽  
Poly Lactic Acid ◽  
Acid Complex ◽  
Main Obstacle ◽  
Industrial Areas

Poly(lactic acid) (PLA) fiber, owing to its biocompatibility and biodegradability, could be widely used in many related industrial areas. However, high brittleness has been the main obstacle to expanding its applications. So in this paper, carbon nanotube (CNT) nanocapsules were designed to toughen PLA and further reported their effect on the crystallization behavior and mechanical properties of PLA complex fiber. These designed CNT nanocapsules successfully solved the agglomeration of CNTs within the PLA matrix as well as the compatibility issue. In addition, the morphological, mechanical, optical and thermal properties of PLA complex fibers were also studied. The addition of CNT nanocapsules obviously improved the crystallization behavior of PLA fiber. Furthermore, compared with pure PLA, the tensile strength of PLA complex fiber was enhanced by 30.62% and the elongation by 32.2%, so the designed CNT nanocapsules could be used as a toughener for PLA fiber. This research benefits the extension of PLA applications where toughness is an important factor.

scholarly journals A study on the mechanical, thermal properties and crystallization behavior of poly(lactic acid)/thermoplastic poly(propylene carbonate) polyurethane blends

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 46183-46194 ◽  
Author(s):  
Jia Yang ◽  
Hongwei Pan ◽  
Xin Li ◽  
Shulin Sun ◽  
Huiliang Zhang ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Impact Strength ◽  
Propylene Carbonate ◽  
Crystallization Behavior ◽  
Raw Materials ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Poly Propylene ◽  
The Impact

PPCU was prepared by using PPC and polyols as the raw materials and diphenyl-methane-diisocyanate (MDI) as the extender chain. The impact strength and elongation at break of PLA were remarkably enhanced by blending with PPCU.

Sign in / Sign up

Export Citation Format

Share Document