Influence of a Phenethyl-Bridged DOPO Derivative on the Flame Retardancy, Thermal Properties, and Mechanical Properties of Poly(lactic acid)

2016 ◽  
Vol 55 (40) ◽  
pp. 10803-10812 ◽  
Author(s):  
Lijuan Long ◽  
Jingbo Yin ◽  
Wentao He ◽  
Shuhao Qin ◽  
Jie Yu
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chaitra Venkatesh ◽  
Yuanyuan Chen ◽  
Zhi Cao ◽  
Shane Brennan ◽  
Ian Major ◽  
...  

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.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1893 ◽  
Author(s):  
Přemysl Menčík ◽  
Radek Přikryl ◽  
Ivana Stehnová ◽  
Veronika Melčová ◽  
Soňa Kontárová ◽  
...  

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”.


2017 ◽  
Vol 88 (14) ◽  
pp. 1616-1627 ◽  
Author(s):  
Shu-qiang Liu ◽  
Gai-hong Wu ◽  
Yun-chao Xiao ◽  
Hong-xia Guo ◽  
Fen-juan Shao

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.


2012 ◽  
Vol 21 (1) ◽  
pp. 303-311 ◽  
Author(s):  
Jyh-Horng Wu ◽  
Ming-Shien Yen ◽  
Chien-Pang Wu ◽  
Chia-Hao Li ◽  
M. C. Kuo

2019 ◽  
Vol 19 (11) ◽  
pp. 7074-7082 ◽  
Author(s):  
Tao Yu ◽  
Changqing Hu ◽  
Yan Li

In this work, 9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide (DOPO) was covalently grafted onto the surface of graphene to get modified graphene (G-DOPO) firstly. The mechanical properties and flame retardancy of jute/poly(lactic acid) (PLA) composite with G-DOPO were studied. According to Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), it was confirmed that DOPO was grafted on the surface of graphene successfully. Thermogravimetric analysis (TGA) results demonstrated that the residue char of the composites increased with the addition of G-DOPO. The total heat release (THR) of the composite was significantly reduced and the limiting oxygen index (LOI) increased after adding G-DOPO into the composite. Moreover, the mechanical properties results showed that the comprehensive effects of G-DOPO on the interface enhancement and matrix toughness were found.


2013 ◽  
Vol 1499 ◽  
Author(s):  
Eda Acik ◽  
Ulku Yilmazer

ABSTRACTTernary nanocomposites of poly (lactic acid) (PLA) were produced by melt blending with two types of elastomers and five types of organoclays to obtain improved mechanical properties such as tensile strength, modulus and impact strength. One of the elastomers is a random copolymer of ethylene and glycidyl methacrylate (E-GMA) and the other one is a random terpolymer of ethylene-butyl acrylate-maleic anhydride (E-BA-MAH). Organically modified montmorillonites (OMMT) were utilized as nanofillers. XRD, DSC, tensile and impact tests were done on the injection molded samples. FTIR, SEM and TEM analyses are still in progress. As preliminary results, thermal analysis showed that the addition of compatibilizers and organoclays does not have a distinct effect on the thermal properties of the composites, and no evidence of nucleation activity of compatibilizers or organoclays was found. For all types of organoclays, the nanocomposites produced with E-GMA exhibited better mechanical properties in comparison to nanocomposites containing E-BA-MAH, especially for the impact strength.


RSC Advances ◽  
2016 ◽  
Vol 6 (18) ◽  
pp. 14852-14858 ◽  
Author(s):  
Yu Cao ◽  
Yaqing Ju ◽  
Fenghui Liao ◽  
Xiaoxun Jin ◽  
Xiu Dai ◽  
...  

A novel nanorod-shaped hybrid flame retardant (NRH-FR) was synthesized by the reaction of benzenephosphinic acid with powdery aluminium hydroxide and the PLA/NRH-FR nanocomposites with good flame retardancy and mechanical property were prepared.


Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1514 ◽  
Author(s):  
Franciszek Pawlak ◽  
Miguel Aldas ◽  
Juan López-Martínez ◽  
María Dolores Samper

A method to modify polymers is that of introducing fibers in a matrix to produce a fiber-reinforced polymer (FRP). Consequently, the aim of this work was to study the compatibility effect of four coupling agents on wool FRP properties, using poly(lactic acid) plasticized with maleinized linseed oil as polymer matrix. The content of wool assessed was 1 phr. The compatibilizers were (3-(2-aminoethylamino)propyl)-trimethoxysilane, trimethoxy (2-(7-oxabicyclo (4.1.0)hept-3-yl) ethyl) silane, tris(2-methoxyethoxy)(vinyl) silane and titanium (IV) (triethanolaminate)isopropoxide. Initially, wool was modified with coupling agents in an acetone/water (50/50) solution. Mechanical properties were evaluated by tensile and flexural properties, hardness by Shore D measurement and impact resistance by Charpy’s energy. Differential scanning calorimetry, dynamic thermo-mechanical analysis, and thermogravimetric analysis were conducted to evaluate the interaction among components and the effect of the coupling agents on the thermal properties of the original material. Color, wettability and scanning electron microscopy were used to describe physical and microstructural properties. Modification of fibers allows achieving improved mechanical properties and changes the thermal properties of the FRPs slightly. Coupling agent treatment helps to formulate PLA–MLO and sheep wool materials and to improve their performance, thereby creating a broader spectrum of applications for PLA maintaining the bio-based character of the material.


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