scholarly journals Poly(L-lactic acid) Reinforced with Hydroxyapatite and Tungsten Disulfide Nanotubes

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3851
Author(s):  
Ofek Golan ◽  
Hila Shalom ◽  
Ifat Kaplan-Ashiri ◽  
Sidney R. Cohen ◽  
Yishay Feldman ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Food Packaging ◽  
Bone Repair ◽  
Composite Films ◽  
Crystalline Polymer ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Tissue Engineering Scaffolds ◽  
Hardness Tests

Poly(L-lactic acid) (PLLA) is a biocompatible, biodegradable, and semi-crystalline polymer with numerous applications including food packaging, medical implants, stents, tissue engineering scaffolds, etc. Hydroxyapatite (HA) is the major component of natural bone. Conceptually, combining PLLA and HA could produce a bioceramic suitable for implants and bone repair. However, this nanocomposite suffers from poor mechanical behavior under tensile strain. In this study, films of PLLA and HA were prepared with small amounts of nontoxic WS2 nanotubes (INT-WS2). The structural aspects of the films were investigated via electron microscopy, X-ray diffraction, Raman microscopy, and infrared absorption spectroscopy. The mechanical properties were evaluated via tensile measurements, micro-hardness tests, and nanoindentation. The thermal properties were investigated via differential scanning calorimetry. The composite films exhibited improved mechanical and thermal properties compared to the films prepared from the PLLA and HA alone, which is advantageous for medical applications.

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.

The effect of carbon nanotubes-grafted lactide on the mechanical and thermal properties of poly (lactic acid) biocomposites

2017 ◽  
Vol 36 (9) ◽  
pp. 655-666 ◽  
Author(s):  
Gaihong Wu ◽  
Shuqiang Liu ◽  
Xiongying Wu ◽  
Xuemei Ding
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Composite Films ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Wide Range ◽  
Ft Ir ◽  
The Fourier Transform ◽  
Flexible Fabrication

Poly(lactic acid) (PLA) derived from renewable crops is a promising substitute for petroleum-based products. Although PLA exhibits positive features, it also possesses drawbacks, such as brittleness, which hinder its extension in specific applications. In this study, lactide (LA) was used to graft carbon nanotubes (CNTs) to reinforce PLA. Under catalysis, LA was polymerized into PLA through ring-opening polymerization and simultaneously was grafted onto CNTs to obtain CNTs modified by LA (LA/CNTs). And the modified CNTs were used to prepare PLA composite films (LA/CNTs/PLA). Analysis of the Fourier transform infrared spectra (FT-IR) of the modified CNTs indicated that LA was grafted with the nanotubes. The scanning electron microscopy images showed that the modified CNTs were compatible and homogeneously dispersed in the PLA matrix. The excellent dispersibility and compatibility of the CNTs led to good interfacial adhesion, which directly enhanced the mechanical properties of PLA. The addition of CNTs also improved the thermal properties of PLA. This research aims to ameliorate the mechanical and thermal properties of PLA and provides basis for flexible fabrication of bio-based PLA materials for a wide range of applications.

Starch–PVA Nanocomposite Film Incorporated with Cellulose Nanocrystals and MMT: A Comparative Study

2016 ◽  
Vol 12 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Nooshin Noshirvani ◽  
Babak Ghanbarzadeh ◽  
Hadi Fasihi ◽  
Hadi Almasi
Keyword(s):  
Thermal Properties ◽  
Food Packaging ◽  
Moisture Sorption ◽  
Water Vapor Permeability ◽  
Nanocrystalline Cellulose ◽  
Nanocomposite Films ◽  
Vapor Permeability ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry

Abstract The goal of this work was to compare the barrier, mechanical, and thermal properties of two types of starch–polyvinyl alcohol (PVA) nanocomposites. Sodium montmorillonite (MMT) and nanocrystalline cellulose were chosen as nanoreinforcements. X-ray diffraction (XRD) test showed well-distributed MMT in the starch–PVA matrix, possibly implying that the clay nanolayers formed an exfoliated structure. The moisture sorption, solubility and water vapor permeability (WVP) studies revealed that the addition of MMT and nanocrystalline cellulose reduced the moisture affinity of starch–PVA biocomposite. At the level of 7 % MMT, the nanocomposite films showed the highest ultimate tensile strength (UTS) (4.93 MPa) and the lowest strain to break (SB) (57.65 %). The differential scanning calorimetry (DSC) results showed an improvement in thermal properties for the starch–PVA–MMT nanocomposites, but not for the starch–PVA–NCC nanocomposites. Results of this study demonstrated that the use of MMT in the fabrication of starch–PVA nanocomposites is more favorable than that of nanocrystalline cellulose to produce a desirable biodegradable film for food packaging applications.

Poly(Lactic Acid)/Poly(Vinyl Alcohol)/Graphene Nanocomposites

2018 ◽  
Vol 773 ◽  
pp. 10-14 ◽  
Author(s):  
Jalupak Rattanakot ◽  
Pranut Potiyaraj
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Vinyl Alcohol ◽  
Testing Machine ◽  
Poly Lactic Acid ◽  
Poly Vinyl Alcohol ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Graphene Nanocomposites

Poly(lactic acid) (PLA) is an interesting material as an environmentally-friendly replacement of petroleum-based polymers. However, some properties need improvements in order to commercially utilized PLA. In this work, graphene is used as a reinforcing filler and poly(vinyl alcohol) is used as a carrier to enhance dispersion of graphene in PLA matrix. The addition of graphene aims at improving the mechanical and thermal properties of PLA. The functional groups of graphene were characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The mechanical property testing was performed using a universal testing machine. The thermal properties were measured through differential scanning calorimetry (DSC). As a result, the Young’s modulus and the thermal properties of PLA composites increased as the amount of graphene in the composites increased due to improved dispersion of graphene in PLA matrix.

scholarly journals Characterization of Electrospun Novel Poly(ester-ether) Copolymers: 1,4-Dioxan-2-one and D,L-3-Methyl-1,4-dioxan-2-one

2011 ◽  
Vol 6 (4) ◽  
pp. 155892501100600 ◽  
Author(s):  
Patricia S. Wolfe ◽  
Yemanlall Lochee ◽  
Dhanjay Jhurry ◽  
Archana Bhaw-Luximon ◽  
Gary L. Bowlin
Keyword(s):  
Thermal Properties ◽  
Mechanical Performance ◽  
Peak Stress ◽  
Uniaxial Tensile ◽  
Mechanical And Thermal Properties ◽  
Scanning Electron Micrographs ◽  
Scanning Calorimetry ◽  
Tissue Engineering Scaffolds ◽  
Modulated Differential Scanning Calorimetry ◽  
Uniaxial Tensile Testing

Introduction: Because tissue engineering scaffolds serve as a temporary environment until new tissue can be formed, their mechanical performance, thermal properties, and biocompatibility are critical for maintaining their functionality. The goal of this study was to electrospin scaffolds from copolymers containing varying amounts of 1,4-Dioxan-2-one (DX) and D,L-3-Methyl-1,4-dioxan-2-one (DL-3-MeDX), and characterize their mechanical and thermal properties. Methods and Results: Image tool analysis of scanning electron micrographs revealed the presence of DL-3-MeDX causes the fiber diameter of the scaffold to decrease as compared to polydioxanone (PDO). Uniaxial tensile testing revealed increasing amounts of DL-3-MeDX in the copolymer decreases scaffold peak stress, strain at break and toughness. Modulated differential scanning calorimetry was used for thermal analysis of the scaffolds and showed that increasing amounts of DL-3-MeDX causes a decrease in the melting as well as crystallization temperatures. Conclusion: Based on the results of the mechanical and thermal properties of these copolymer scaffolds, it is evident that these constructs could be functional in a variety of biomedical engineering applications.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

The influence of adding long basalt fiber on the mechanical and thermal properties of composites based on poly(oxymethylene)

2018 ◽  
Vol 33 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Patrycja Bazan ◽  
Stanisław Kuciel ◽  
Mariola Sądej
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Average Length ◽  
Flexural Modulus ◽  
Basalt Fiber ◽  
Charpy Impact ◽  
Mechanical And Thermal Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Atr Spectroscopy

The work has evaluated the possibility of the potential reinforcing of poly(oxymethylene) (POM) by basalt fibers (BFs) and influence of BFs addition on thermal properties. Two types of composites were produced by injection molding. There were 20 and 40 wt% long BFs content with an average length of 1 mm. The samples were made without using a compatibilizer. In the experimental part, the basic mechanical properties (tensile strength, modulus of elasticity, strain at break, flexural modulus, flexural strength, and deflection at 3.5% strain) of composites based on POM were determined. Tensile properties were also evaluated at three temperatures −20°C, 20°C, and 80°C. The density and Charpy impact of the produced composites were also examined. The influence of water absorption on mechanical properties was investigated. Thermal properties were conducted by the differential scanning calorimetry, thermal gravimetric analysis, and fourier transform infrared (FTIR)-attenuation total reflection (ATR) spectroscopy analysis. In order to make reference to the effects of reinforcement and determine the structure characteristics, scanning electron microscopy images were taken. The addition of 20 and 40 wt% by weight of fibers increases the strength and the stiffness of such composites by more than 30–70% in the range scale of temperature. Manufactured composites show higher thermal and dimensional stability in relation to neat POM.

Enhanced properties of poly(lactic acid) by concurrent addition of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate

2019 ◽  
pp. 089270571986827 ◽  
Author(s):  
Mehrnoush Monshizadeh ◽  
Sajad Seifi ◽  
Iman Hejazi ◽  
Javad Seyfi ◽  
Hossein Ali Khonakdar
Keyword(s):  
Lactic Acid ◽  
Layered Double Hydroxide ◽  
Food Packaging ◽  
Synergistic Effects ◽  
Poly Lactic Acid ◽  
Solution Casting ◽  
Scanning Calorimetry ◽  
Concurrent Use ◽  
Triethyl Citrate ◽  
Double Hydroxide

Synergistic effects of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate (TEC) on the properties of poly(lactic acid) (PLA) were demonstrated. PLA/LDH nanocomposites in the absence and presence of TEC were fabricated via solution casting technique. Morphological analysis revealed that as the LDH concentration increases, the number of aggregations is also increased; however, introduction of TEC considerably enhanced the dispersion quality of LDHs. Differential scanning calorimetry results showed that the addition of LDH and TEC had no significant influence on the crystallinity of nanocomposites obtained from solution casting. In contrast, once the samples were cooled from melt, the concurrent use of LDH and TEC led to a dramatic enhancement in the crystallinity of PLA ( X c = 55.5%). Moreover, the LDH nanoparticles counterbalanced the adverse effects of plasticization by TEC leading to enhanced toughness of the final nanocomposites. LDH had also a positive influence on thermal stability of PLA, indicating the heat-insulating role of LDH particles. In conclusion, the concurrent use of LDH and TEC could extend the applicability of PLA especially in food packaging applications.

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