scholarly journals Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid)

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xingxun Liu ◽  
Tongxin Wang ◽  
Laurence C. Chow ◽  
Mingshu Yang ◽  
James W. Mitchell
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Inorganic Filler ◽  
Homogeneous Distribution ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Tensile Tester

Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

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.

Weldability of pipe grade polyethylenes as realized from thermal and mechanical properties assessments

2016 ◽  
Vol 36 (8) ◽  
pp. 853-860 ◽  
Author(s):  
Vahabodin Goodarzi ◽  
Zahed Ahmadi ◽  
Mohammad Reza Saeb ◽  
Farkhondeh Hemmati ◽  
Mehdi Ghaffari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Molecular Weight ◽  
Aging Process ◽  
Pipe Production ◽  
Lamellar Thickness ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Injection Molded ◽  
The One

Abstract Since polyethylene (PE) has been widely accepted for the production of high-pressure fluid conveying pipelines, studies devoted to weldability of PE connections were always of major importance. In this study, two industrial PE grades designed for pipe production, namely PE80 and PE100, were injection molded, cut, and then welded as PE100-PE100, PE100-PE80, and PE80-PE80. The heat-welded joints were assessed by differential scanning calorimetry and tensile measurements. The results obtained from thermal and mechanical analyses were compared with equivalents for aged samples. Thermal analysis revealed that the melting point of the PE100-PE100 sample is obviously larger than the one for the PE80-PE80 joint, for the PE80 chains deteriorate the crystallization of PE100. Further, the PE80-PE80 sample showed the lowest lamellar thickness and crystalline molecular weight among the studied joints. The aging process was found to increase lamellar thickness and molecular weight, though in the PE100-PE100 sample such quantities very limitedly increased. The yield stress of aged joints was higher than that for just-prepared samples, while an inverse trend was seen for strain at break. From a practical viewpoint, the PE100-PE100 welds offer better properties.

scholarly journals Poly(lactic acid) polymer stars built from early generation dendritic polyols

2013 ◽  
Vol 91 (6) ◽  
pp. 392-397 ◽  
Author(s):  
Genny E. Keefe ◽  
Jean-d'Amour K. Twibanire ◽  
T. Bruce Grindley ◽  
Michael P. Shaver
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Poly Lactic Acid ◽  
Reactive Site ◽  
Scanning Calorimetry ◽  
Early Generation ◽  
Sequential Reaction ◽  
Cyclic Esters ◽  
Total Molecular Weight

A family of polymer stars has been prepared from early generation dendritic cores with four, six, and eight arms. Four dendritic cores were prepared from the sequential reaction of a multifunctional alcohol with a protected anhydride, followed by deprotection to afford two or three new alcohol functionalities per reactive site. These cores were used as initiators for the tin-catalyzed ring-opening polymerization of l-lactide and rac-lactide to afford isotactic and atactic degradable stars, respectively. Two series of stars were prepared for each monomer, either maintaining total molecular weight or number of monomer units per arm. The polymers were characterized by NMR spectroscopy, light-scattering gel-permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Our results support previous work that suggests that the length of the arms dictates thermal properties rather than the total molecular weight of the star. Little effect was noted between aromatic and aliphatic cores, presumably due to the flexibility of the rest of the core molecule. We have shown that early generation dendrimers can serve as excellent core structures for building core-first polymer stars via the ring-opening of cyclic esters.

scholarly journals Analysis of the Degradation During Melt Processing of PLA/Biosilicate® Composites

2019 ◽  
Vol 3 (2) ◽  
pp. 52 ◽  
Author(s):  
Eduardo H. Backes ◽  
Laís de N. Pires ◽  
Lidiane C. Costa ◽  
Fabio R. Passador ◽  
Luiz A. Pessan
Keyword(s):  
Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Melt Processing ◽  
Poly Lactic Acid ◽  
Processing Route ◽  
Mechanical Resistance ◽  
Scanning Calorimetry ◽  
Oxidative Reactions ◽  
Bioactive Composites ◽  
Internal Mixer

Poly (lactic acid) (PLA)/bioactive composites are emerging as new biomaterials since it is possible to combine stiffness, mechanical resistance, and bioactive character of the bioglasses with conformability and bioabsorption of the PLA. In this study, PLA/Biosilicate® composites were prepared using a melt-processing route. The processability and properties were evaluated aiming to produce composites with bioactive properties. Two different PLA (PLA 2003D and PLA 4043D) were tested with the addition of 1 wt. % of Biosilicate®. Both materials presented a huge reduction in melt viscosity after internal mixer processing. The degradation effects of the addition of Biosilicate® in the PLAs matrices were evaluated using zeta potential tests that showed a very high liberation of ions, which catalyzes PLA thermo-oxidative reactions. To understand the extension of degradation effects during the processing, the composites were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and rheological tests. GPC results showed that PLA with the lowest residual acid content (RAC), PLA 2003D, presented higher thermal stability, higher molecular weight, and viscosity baseline compared to PLA 4043D. The composites showed a significant decrease in molecular weight for both PLA with the addition of Biosilicate®. TGA results showed that Biosilicate® might have reduced the activation energy to initiate thermodegradation reactions in PLAs and it occasioned a reduction in the Tonset by almost 40 °C. The DSC results showed that severe matrix degradation and the presence of bioglass did not significantly affect glass transition temperature (Tg), melting temperature (Tm) and crystallinity of PLAs, but it influenced cold crystallization peak (Tcc). In this way, the type of PLA used influences the processability of this material, which can make the production of filaments of this material for 3D printing unfeasible.

Thermal and Mechanical Properties of Cyclized Polybutadiene Dielectrics

1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Infrared Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
The Difference ◽  
Thermal Mechanical Analysis ◽  
Lower Glass Transition Temperature

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.

Morphological, Thermal and Mechanical Properties of Poly(Lactic Acid)/Cellulose/ Nano-Clay Composite

2020 ◽  
Vol 856 ◽  
pp. 331-338
Author(s):  
Sirisart Ouajai ◽  
Suttinun Phongtamrug
Keyword(s):  
Mechanical Properties ◽  
Flexural Modulus ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Nano Clay ◽  
Twin Screw ◽  
Modified Cellulose

This research has focused on the effect of modified cellulose and clay on the thermal and mechanical properties of PLA bio-nanocomposite. Cellulose was chemically modified with silane coupling agent in order to enhance compatiblization with PLA. Successful modification was confirmed by Fourier Transform Infrared Spectroscopy and EDX-SEM. PLA was compounded with various amounts and ratios of the modified cellulose and clay by a twin-screw extruder. Thermal properties of the bio-nanocomposites were characterized by Thermogravimetric Analysis and Differential Scanning Calorimetry. Glass transition temperature of the bio-nanocomposite slightly decreased whereas melting temperature remained constant when the amount of both fillers was increased. In addition, crystallization behaviour of PLA has been influenced by the type and amount of the fillers. Clay showed a greater effect on the crystallization of PLA than the modified cellulose and unmodified one, respectively. The flexural modulus of the composite containing equal amount between clay and cellulose was increased with an increasing in fillers contents. But the flexural and impact strength of composite were gradually decreased with an increase in fillers contents. Variation of clay and cellulose ratio resulted in the change of mechanical properties. The composite containing higher ratio between clay:cellulose or cellulose:clay showed a better mechnical properties comparing to the ratio of clay:cellulose equal to 1:1.

Structure and properties of poly(lactic acid)/poly(lactic acid)-α-cyclodextrin inclusion compound composites

2017 ◽  
Vol 37 (9) ◽  
pp. 897-909
Author(s):  
Li Zhang ◽  
Weijun Zhen ◽  
Yufang Zhou
Keyword(s):  
Lactic Acid ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
Synthesis Conditions ◽  
Cyclodextrin Inclusion ◽  
Comprehensive Performance

Abstract Poly(lactic acid) (PLA) was synthesized using a green catalyst, nano-zinc oxide (ZnO). The optimum synthesis conditions of PLA were as follows: a stoichiometric amount of 0.5 wt% of nano-ZnO, polymerization time of 14 h, and polymerization temperature of 170°C. Gel permeation chromatography results showed that the weight-average molecular weight (Mw) of PLA was 13,072 g/mol with a polydispersity index (PDI) of 1.7. Furthermore, PLA-α-cyclodextrin inclusion compounds (PLA-CD-ICs) were prepared by ultrasonic co-precipitation techniques. X-ray diffraction analysis and Fourier transform infrared spectroscopy demonstrated the change in lattice of α-CD from a cage configuration to a tunnel structure and the existence of some physical interactions between α-CD and PLA in the PLA-CD-ICs. To enhance the crystallization properties of PLA, PLA/PLA-CD-IC composites were blended with different contents of PLA-CD-ICs as nucleating agents. The crystallization behavior and comprehensive performance were investigated by differential scanning calorimetry, polarized optical microscopy, tensile testing, dynamic mechanical analysis, and scanning electron microscopy. Compared to PLA, the crystallinities of PLA/PLA-CD-IC composites were increased by 24.0%, 26.3%, 27.3%, and 31.8%. The results of all the analyses proved that PLA-CD-ICs were useful as green organic nucleators and improved the comprehensive performance of PLA materials.

Pad Degradation During CMP Process: Effect of Soak in Slurry and Water on Thermal and Mechanical Properties of the CMP Pads

2003 ◽  
Vol 767 ◽  
Author(s):  
A. Tregub ◽  
G. Ng ◽  
M. Moinpour
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Thermal Gravimetric Analysis ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
Thermal And Mechanical Properties ◽  
Thermal Gravimetric ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermal Mechanical Analysis

AbstractSoak of polyurethane-based CMP pads in tungsten slurry and de-ionized water and its effect on retention of thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis (DMA), Thermal Mechanical Analysis (TMA), Thermal Gravimetric Analysis (TGA), and Modulated Differential Scanning Calorimetry (MDSC). Simultaneous cross-linking and plastisizing due to soak were established using DMA and MDSC analysis. The stable operating temperature range and its dependence on soak time were determined using TMA analysis. Substantial difference in diffusion behavior of the “soft” and “hard” pads was discovered: diffusion into the hard pads followed Fickian law [1], while diffusion into the multi-layer soft pads was dominated by the fast filling of the highly porous pad surface with liquid.During a traditional CMP process, which involves application of polishing pads and slurry, the pad properties can be substantially and irreversibly changed as the result of slurry/rinse water absorption.The retention of the pad properties after exposure was monitored using such thermal and mechanical techniques, as Thermal Mechanical Analysis (TMA), Dynamical Mechanical Analysis (DMA), Modulated Differential Scanning Calorimetry (MDSC), Thermal Gravimetric Analysis (TGA).

Curing behavior, thermal, and mechanical properties of N,N′-(4,4′-diphenylmethane)bismaleimide/2,2′-diallylbisphenol A/3-allyl-5,5-dimethylhydantoin resin system

2019 ◽  
Vol 32 (6) ◽  
pp. 631-644
Author(s):  
Xiangyu Liu ◽  
Ling Li ◽  
Zibing Chen ◽  
Xianfa Duan ◽  
Yongjian Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Property ◽  
Mechanical Analysis ◽  
Alder Reaction ◽  
Resin System ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Curing Behavior ◽  
Energy Formula ◽  
Diallylbisphenol A

The 3-allyl-5,5-dimethylhydantoin (ADMH) was synthesized and characterized by Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance (NMR), and 13C-NMR spectroscopy. Then, the ADMH was used to modify the N, N′-(4,4′-diphenylmethane)bismaleimide (BDM)/2,2′-diallylbisphenol A (DABPA) resin to obtain the BDM/DABPA/ADMH resin system (BDA). The curing behavior was investigated by non-isothermal differential scanning calorimetry and the activation energy ([Formula: see text]) was obtained by Kissinger and Ozawa models. The thermomechanical property was measured by dynamic mechanical analysis. Analysis of the data revealed the complexity of the curing reaction, which was firstly dominated by the Ene reaction of allyl and C=C double bond at low and medium temperatures and was further governed by the Diels–Alder reaction and the anionic imide oligomerization occurred at high temperatures. The results demonstrated that 1-BDA had the best thermal and mechanical properties exhibiting excellent modification effect of ADMH.

scholarly journals The research of the thermal and mechanical properties of materials produced by 3D printing method

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1211-1216
Author(s):  
Adam Gnatowski ◽  
Agnieszka Kijo-Kleczkowska ◽  
Henryk Otwinowski ◽  
Piotr Sikora
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Polymeric Materials ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Properties Of Materials ◽  
Butadiene Styrene

A comparative analysis of thermal properties of semi-crystalline and amorphous polymeric materials was carried out. Samples were produced using 3D printing technology on the SIGNAL-ATMAT printer. The following polymeric materials were used to make the samples: thermoplastic polyurethane elastomer, acryloni-trile-butadiene-styrene copolymer, Laywood, ethylene terephthalate, poly (lactic acid). The materials were tested for their thermal and mechanical properties. The research included the analysis of thermal properties by differential scanning calorimetry of manufactured materials. The tensile strength also was determined.

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