scholarly journals Thermal and Mechanical Properties of Silica–Lignin/Polylactide Composites Subjected to Biodegradation

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2257 ◽  
Author(s):  
Aleksandra Grząbka-Zasadzińska ◽  
Łukasz Klapiszewski ◽  
Sławomir Borysiak ◽  
Teofil Jesionowski
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Crystallization Behavior ◽  
Composite Films ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Hybrid Filler ◽  
Hybrid Fillers ◽  
Morphology Of Films

In this paper, silica–lignin hybrid materials were used as fillers for a polylactide (PLA) matrix. In order to simulate biodegradation, PLA/hybrid filler composite films were kept in soil of neutral pH for six months. Differential scanning calorimetry (DSC) allowed analysis of nonisothermal crystallization behavior of composites, thermal analysis provided information about their thermal stability, and scanning electron microscopy (SEM) was applied to define morphology of films. The influence of biodegradation was also investigated in terms of changes in mechanical properties and color of samples. It was found that application of silica–lignin hybrids as fillers for PLA matrix may be interesting not only in terms of increasing thermal stability, but also controlled biodegradation. To the best knowledge of the authors, this is the first publication regarding biodegradation of PLA composites loaded with silica–lignin hybrid fillers.

scholarly journals The Effect of Boron Nitride on the Thermal and Mechanical Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 940 ◽  
Author(s):  
Mualla Öner ◽  
Gülnur Kızıl ◽  
Gülşah Keskin ◽  
Celine Pochat-Bohatier ◽  
Mikhael Bechelany
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Boron Nitride ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Filler Concentration ◽  
Gravimetric Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry

The thermal and mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) composites filled with boron nitride (BN) particles with two different sizes and shapes were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), thermal gravimetric analysis (TGA) and mechanical testing. The biocomposites were produced by melt extrusion of PHBV with untreated BN and surface-treated BN particles. Thermogravimetric analysis (TGA) showed that the thermal stability of the composites was higher than that of neat PHBV while the effect of the different shapes and sizes of the particles on the thermal stability was insignificant. DSC analysis showed that the crystallinity of the PHBV was not affected significantly by the change in filler concentration and the type of the BN nanoparticle but decreasing of the crystallinity of PHBV/BN composites was observed at higher loadings. BN particles treated with silane coupling agent yielded nanocomposites characterized by good mechanical performance. The results demonstrate that mechanical properties of the composites were found to increase more for the silanized flake type BN (OSFBN) compared to silanized hexagonal disk type BN (OSBN). The highest Young’s modulus was obtained for the nanocomposite sample containing 1 wt.% OSFBN, for which increase of Young’s modulus up to 19% was observed in comparison to the neat PHBV. The Halpin–Tsai and Hui–Shia models were used to evaluate the effect of reinforcement by BN particles on the elastic modulus of the composites. Micromechanical models for initial composite stiffness showed good correlation with experimental values.

scholarly journals Thermal Properties of TiO2NP/CNT/LDPE Hybrid Nanocomposite Films

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1270 ◽  
Author(s):  
Moustafa Zagho ◽  
Mariam AlMaadeed ◽  
Khaliq Majeed
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Filler Concentration ◽  
Gravimetric Analysis ◽  
Melt Mixing ◽  
Hybrid Filler ◽  
Hybrid Fillers ◽  
Multi Walled Carbon Nanotubes

This work aims to investigate the effect of hybrid filler concentration on the thermal stability of low-density polyethylene (LDPE) matrices. LDPE-based composite films were synthesized by melt mixing, followed by compression molding, to study the influence of titanium oxide nanoparticles (TONPs) and/or multi-walled carbon nanotubes (CNTs) on the thermal properties of LDPE matrices. Fourier transform infrared (FTIR) spectroscopy confirmed the slight increase in the band intensities after TONP addition and a remarkable surge after the incorporation of CNTs. The value of crystallization temperature (Tc) was not modified after incorporating TONPs, while an enhancement was observed after adding the hybrid fillers. The melting temperature (Tm) was not changed after introducing the CNTs and CNT/TONP hybrid fillers. The percentage crystallinity (Xc %) was increased by 4% and 6%, after incorporating 1 wt % and 3 wt % CNTs, respectively. The TONP incorporation did not modify the Xc %. Moreover, thermal gravimetric analysis (TGA) thermograms confirmed the increased thermal stability after introducing CNTs and hybrid fillers compared to TONP incorporation.

scholarly journals Hydroxyapatite/polyetheretherketone nanocomposites for selective laser sintering: Thermal and mechanical performances

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 542-549
Author(s):  
Wenwen Lai ◽  
Yan Wang ◽  
Hua Fu ◽  
Junkun He
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Flexural Modulus ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Mechanical Performances ◽  
Nanocomposite Powders

AbstractIn this article, the thermal and mechanical properties of hydroxyapatite (HA)/polyetheretherketone (PEEK) nanocomposites were investigated. The surface of the HA particles was modified by stearic acid. Subsequently, the modified HA and PEEK were ultrasonically dispersed in ethanol and then subjected to drying and ball milling treatments. By controlling the concentration of modified HA, HA/PEEK nanocomposite powders containing various amounts of modified HA were successfully prepared. The tensile strength, impact strength, and flexural strength of the nanocomposite reached maximum values at 2.5 wt% HA and were 18.5%, 38.2%, and 5.7% higher than those of the pure PEEK, respectively. Moreover, the flexural modulus of the HA/PEEK nanocomposites increased at 2.5 wt% HA and was approximately 30% higher than that of the pure PEEK. The thermal property measurements (differential scanning calorimetry and thermogravimetric analysis) showed that the nanocomposites with 2.5 wt%-modified HA exhibited enhanced thermal stability as compared to the pure PEEK, showing potential for selective laser sintering.

Properties and Nonisothermal Crystallization Behavior of Nucleated Polylactide Biodegradable Composite Films

2012 ◽  
Vol 488-489 ◽  
pp. 671-675 ◽  
Author(s):  
Worasak Phetwarotai ◽  
Duangdao Aht-Ong
Keyword(s):  
Tensile Properties ◽  
Cooling Rate ◽  
Crystallization Behavior ◽  
Composite Films ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Precipitated Calcium Carbonate ◽  
Biodegradable Composite

Polylactide biodegradable composite films were prepared via melt extrusion using a twin screw extruder. The effects of type and content of nucleating agent and cooling rate on the thermal and tensile properties of these films were investigated. Two types of nucleating agent, talc and nano precipitated calcium carbonate (NPCC), were studied at various contents from 0 to 2.0 phr. Nonisothermal crystallization behavior of composites was characterized by a differential scanning calorimetry (DSC). The cooling rate was varied from 1 to 10°C/min. The results indicated that the presence of nucleating agent significantly influenced on thermal and tensile properties of the PLA composite films. DSC thermograms revealed that the addition of nucleating agent on the PLA films led to an increase of crystallization temperature (Tc), crystallization rate, and degree of crystallization (χc) compared to the neat PLA. These behaviors could be noticed in both the nucleated PLA films with NPCC and talc. In contrast, the Tc and crystallization half-time (t1/2) of these films significantly decreased when the cooling rate increased from 1 to 10°C/min. However, thermal stability of the films decreased when the nucleating agent content increased, especially that of the composites with NPCC.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

Expanded vermiculite-filled flexible polymer composites

2021 ◽  
pp. 009524432110290
Author(s):  
Mukaddes Sevval Cetin ◽  
Ozan Toprakci ◽  
Omer Suat Taskin ◽  
Abdullah Aksu ◽  
Hatice Aylin Karahan Toprakci
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Contact Angle ◽  
Polymer Composites ◽  
Flame Retardancy ◽  
Composite Films ◽  
Filler Concentration ◽  
High Shear ◽  
Flexible Polymer ◽  
Shear Mixing

This study focuses on the fabrication and characterization of vermiculite-filled flexible polymer composites. Exfoliated vermiculite was incorporated into triblock thermoplastic elastomer copolymer, styrene- b-(ethylene- co-butylene)- b-styrene (SEBS), at various levels from 1 to 15 wt% by a high shear mixer. The composite films were obtained by the combination of solvent casting and compression molding. The morphological, structural, thermal, and mechanical properties and contact angle of the composites were determined. Some micro-morphological differences were observed between the samples and the difference was assumed to be caused by high shear mixing and filler concentration. High shear mixing was found effective in terms of the detachment of vermiculite layers at all concentrations. However, at low filler loading, that behavior was more obvious. At 1 wt% filler concentration, mechanical properties increased that was probably caused by good filler-matrix interaction stemmed from smaller particle size. At higher vermiculite concentrations, fillers found to show agglomerations that led to a decrease in mechanical strength and strain at break. Elastic and secant modulus showed an increasing trend. Contact angle measurements were carried out to determine the oleophilic character of the samples. An increase in the vermiculite content resulted in higher oleophilic character and the lowest contact angle was obtained at 15 wt% VMT loading. In addition to these, thermal stability, thermal dimensional stability and flame retardancy were improved by the incorporation of VMT. 15 wt% vermiculite-filled sample showed the best performance in terms of thermal stability and flame retardancy.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

Mechanical and microstructural properties of polystyrene based composites: positron lifetime spectroscopic and DSC studies

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Abdullah Mohammed Ali Mohammed Altaweel ◽  
Jaya Madhu Raj ◽  
Malalvalli Nagarajaiah Chandrashekara ◽  
Puttegowda Ramya ◽  
Parthasarathy Sampathkumaran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Free Volume ◽  
Positron Lifetime ◽  
Tensile Modulus ◽  
Silica Content ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Microstructural Property ◽  
Calcium Aluminosilicate

Abstract Polystyrene (PS) based composites respectively with cenosphere (CS) and calcium aluminosilicate (CAS) as fillers were studied using the positron lifetime technique to reveal the correlation between free volume, a microstructural property, and mechanical properties of the composites (tensile strength and tensile modulus). The thermal stability of the composites was determined using differential scanning calorimetry. The results showed that addition of CAS filler lead to a significant improvement in the mechanical properties of the composite, whereas addition of CS resulted in improvement in tensile modulus only. Both PS/CAS and PS/CS composites showed enhancement in thermal stability compared with that of the pure PS matrix. The positron results showed that the average free volume size for the PS/CAS composite (at 40 phr CAS) was reduced significantly compared with that of the pure PS. These results are understood in terms of the influence of silica content, filler-matrix interaction, and particle size.

Thermal Stability and Crystallization Behavior of PP/Organoclay Phase Change Composites

2013 ◽  
Vol 785-786 ◽  
pp. 123-126
Author(s):  
Ying Ye ◽  
Kun Yan Wang ◽  
Ge Chang ◽  
Qian Ying Jiang
Keyword(s):  
Thermal Stability ◽  
Phase Change ◽  
Crystallization Behavior ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Blending Method ◽  
Phase Change Composites ◽  
Change Material

Polypropylene/organoclay modified by dodecanol phase change material were prepared by melt blending method. The thermal stability and crystallization behavior was studied by thermogravimetry (TG), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). TG results indicated the window of processing of PP could be improved by adding small amount organoclay modified by dodecanol to the blend. DSC showed the organoclay modified by dodecanol affected the crystallization behavior of PP as heterogeneous nucleation agent. XRD results show that the organoclay modified by dodecanol does not change the crystal structure in the blends but only decrease the intensity of the diffraction peak.

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