Mechanical Properties Of Poly Research Articles

Effects of modified elastin-collagen matrix on the thermal and mechanical properties of Poly (lactic acid)

Poly (lactic acid) (PLA) has distinctive characteristics, including biodegradability, biocompatibility, thermal process ability, high transparency and good film-forming ability. However, PLA has some poor properties that limit its wide applicability. These properties include a low crystallization rate, poor thermal stability, and high brittleness. The main objective of this research was to investigate the effect of a modified elastin-collagen (m-ELA-COLL) matrix on the properties of PLA. The ELA-COLL matrix was extracted from broiler skin waste and modified by grafting using lactic acid monomer to facilitate compatibility with PLA. The extracted and modified ELA-COLL matrix was investigated using FTIR, and α-helix and β-sheet structures were confirmed in both cases (pre- and post-modifications). Modified elastin-collagen dispersed Poly (lactic acid) (PLA-m-ELA-COLL) blend films were prepared using the solution casting method and characterized using DSC and UTM. The effect of m-ELA-COLL as a nucleating agent resulted in the degree of crystallinity improvement of 58.8% with 10 wt% m-ELA/COLL loading, and the elongation at break was improved by 161.3% for PLA-40%-m-ELA-COLL with a tensile strength of 33.75 MPa. The results obtained revealed that the biofilms can be considered as a good candidate to be studied further in the packaging industry.

Bio-derived phosphorous-nitrogen-silicon decorated halloysite nanotube towards enhancing flame retardant, UV-blocking and mechanical properties of poly(lactic acid)

Developing flame retardant and UV-blocking polylactide (PLA) with reinforced mechanical properties is important but challenging. Herein, bio-derived phytic acid was decorated on halloysite nanotube though silane grafting, ring-opening reaction with melamine and then electrostatic interactions with phytic acid. The obtained phopsphorous-nitrogen-silicon decorated halloysite nanotube (PNSiHNT) was incorporated into PLA to prepare PLA composites. The surface modification significantly improved the compatibility between PNSiHNT and PLA, and the flame retardant, UV-shielding and mechanical properties of the composites were enhanced. At 5% mass loading, the peak heat release and total heat release were reduced by 18% and 12% compared to pure PLA, respectively, superior to most phytic acid-based flame retardants. The relevant mechanism analysis showed that PNSiHNT can restrain the emission of combustible volatiles and promote the formation of protective char layer. Moreover, the flame-retardant PLA showed excellent UV-shielding ability with an ultraviolet protection factor (UPF) value of around 120. Due to the reinforcing effect of PNSiHNT and the strong interfacial interactions between PNSiHNT and PLA matrix, the PLA/PNSiHNT showed 77% and 116% increase in tensile strength and elongation at break compared to the bulk PLA. This study provides a strategy for designing bio-derived organic/inorganic systems for enhancing flame retardant, UV-blocking and reinforced PLA.

Influence of Deformation of Metal Matrix on the Mechanical Properties of Poly(Ethylene Terephthalate) Inside It

Influence of Deformation of Metal Matrix on the Mechanical Properties of Poly(Ethylene Terephthalate) Inside It

Effects of Nano- and Micro-sized Calcium Carbonate on the Thermal and Mechanical Properties of Poly(lactic acid)/Poly(butylene adipate-co-terephthalate) with Bi-continuous Phases

Effects of Nano- and Micro-sized Calcium Carbonate on the Thermal and Mechanical Properties of Poly(lactic acid)/Poly(butylene adipate-co-terephthalate) with Bi-continuous Phases

Influence of Coffee Variety and Processing on the Properties of Parchments as Functional Bioadditives for Biobased Poly(butylene succinate) Composites.

Fermented polymers like biobased poly(butylene succinate) (BioPBS) have become more relevant as technical substitutes for ductile petrochemical-based polymers but require biogenic functional additives to deaccelerate undesired thermo-oxidative degradation and keep a fully biobased character. In this paper, the influence of coffee parchment (PMT) from two different varieties and processings on the thermo-oxidative stabilization and mechanical properties of poly(butylene succinate) composites up to 20 wt.-% PMT were investigated. Micronized with a TurboRotor mill, both PMT powders differ in particle size and shape, moisture ab- and adsorption behavior and antioxidative properties. It could be shown that pulped-natural PMT consists partially of coffee cherry residues, which leads to a higher total polyphenol content and water activity. The homogeneous PMT from fully washed processing has a higher thermal degradation resistance but consists of fibers with larger diameters. Compounded with the BioPBS and subsequent injection molded, the fully washed PMT leads to higher stiffness and equal tensile strength but lower toughness compared to the pulped-natural PMT, especially at lower deformation speed. Surprisingly, the fully washed PMT showed a higher stability against thermo-oxidative decomposition despite the lower values in the total phenol content and antioxidative activity. The required antioxidative stabilizers might be extracted at higher temperatures from the PMT fibers, making it a suitable biogenic stabilizer for extrusion processes.

Influence of microbial biomass content on biodegradation and mechanical properties of poly(3-hydroxybutyrate) composites

Biodegradation rates and mechanical properties of poly(3-hydroxybutyrate) (PHB) composites with green algae and cyanobacteria were investigated for the first time. To the authors knowledge, the addition of microbial biomass led to the biggest observed effect on biodegradation so far. The composites with microbial biomass showed an acceleration of the biodegradation rate and a higher cumulative biodegradation within 132 days compared to PHB or the biomass alone. In order to determine the causes for the faster biodegradation, the molecular weight, the crystallinity, the water uptake, the microbial biomass composition and scanning electron microscope images were assessed. The molecular weight of the PHB in the composites was lower than that of pure PHB while the crystallinity and microbial biomass composition were the same for all samples. A direct correlation of water uptake and crystallinity with biodegradation rate could not be observed. While the degradation of molecular weight of PHB during sample preparation contributed to the improvement of biodegradation, the main reason was attributed to biostimulation by the added biomass. The resulting enhancement of the biodegradation rate appears to be unique in the field of polymer biodegradation. The tensile strength was lowered, elongation at break remained constant and Young’s modulus was increased compared to pure PHB.

Influence of Deformation of Metal Matrix on the Mechanical Properties of Poly(Ethylene Terephthalate) Inside It

The influence of different types of deformation of the metal matrix on mechanical behavior of the amorphous PET film upon its transverse compression in the ductile metal matrix has been investigated. Three deformation modes have been probed. In the first case, a disc-shaped polymer specimen has been put between two 5 mm thick discs of the lead–tin alloy and squeezed in the press. In the second and the third cases, planar elongation has been performed in the so called “dead channel”, i.e., the channel with fixed side walls, the film being elongated due to decrease in the width or thickness, respectively. The plots of true yield stress at different draw ratios have formed a common master curve. At high total draw ratio Λ, the true yield stresses have been close for the considered three types of drawing in the metal. At the draw ratio Λ 2.6, the neck has not appeared, and the specimen has been deformed uniformly. When the film in the channel is elongated due to the decrease in thickness at constant width, the specimen width has been mainly decreased during subsequent elongation in the testing machine. When the film in the channel is elongated due to the decrease in width at constant thickness, further elongation has mainly led to the decrease in the specimen thickness. The true stress Σ has been expressed as Σ = Σ0 + KΛ3, with K being a constant. Deformation of the polymer in the channel occurred with the formation of shear bands. At the preliminary draw ratio Λ = 1.82, the bands have been oriented at the angle 21.5° with respect to the stretching axis. The planar elongation has led to abnormally strong deformation softening of the polymer. The drawing has been accompanied by an increase in the elasticity modulus of the polymer. The obtained results have suggested that the macromolecules orientation is the main reason for strain hardening of the polymer.

Thermo-mechanical performance of nanostructured electrospun composites produced from poly(vinyl alcohol) and cellulosic compounds for potential uses as wound dressings

The purpose of this research was to analyze the morphology, thermal and mechanical properties of poly(vinyl alcohol) (PVA)-based electrospun mats reinforced with cellulose acetate (CA) or cellulose nanocrystalline (CNC) for potential applications in wound dressings. Bead-free and water-stable electrospun nanofibers made of blends of PVA and CA or CNC were successfully produced and crosslinked with glutaraldehyde vapor. Crosslinking slightly increased the nanofibers' diameters in order of 43 and 13% for 80/20 PVA/CA and PVA/CNC electrospun mats, respectively, while maintaining their bead-free morphology. Thermogravimetry (TGA) and differential scanning calorimetry (DSC) evaluations were employed to determine the miscibility and the thermal response of the uncrosslinked and crosslinked mats, reporting a reduction in mass loss upon addition of CA and CNC and upon crosslinking process. Polymers' powder and mats (before and after crosslinking) crystallinity was assessed by X-ray diffraction analysis (XRD). Crosslinked mats experienced a slight reduction in crystallinity compared to the uncrosslinked. Static and dynamic tensile strength tests revealed that CA and CNC doped mats enhanced the Young's modulus and lowered deformation at failure compared to pristine PVA electrospun mats. Data from storage modulus (E′) demonstrated the strength of the physical interactions formed between PVA and the cellulosic derivatives (either before and after crosslinking), highlighting the stiffness of CA (231.58 MPa for the 80/20 mat) and, particularly, CNC (742.04 MPa for the 80/20 mat). This research uncovered important information concerning the chemical and physical relation between polymeric matrices and additives, essential for the proper selection of materials for wound dressings production.

Effects of tomato peel extract on morphological, chemical, thermal, and mechanical properties of poly(lactic acid)

Effects of tomato peel extract on morphological, chemical, thermal, and mechanical properties of poly(lactic acid)

Effect of mixing strategy on thermal and mechanical properties of poly(butylene adipate-co-terephthalate)/poly(lactic acid) incorporated with CaCO3 fillers

Effect of mixing strategy on thermal and mechanical properties of poly(butylene adipate-co-terephthalate)/poly(lactic acid) incorporated with CaCO3 fillers

Doping nanocellulose crystal with poly(vinyl alcohol) for water‐resistant composite fibers with enhanced mechanical and dyeing performances

AbstractAcetalization has been commonly adopted to realize the improvement on the water resistance and mechanical properties of poly(vinyl alcohol) (PVA) composite fibers. However, acetalized PVA fibers only have a very low concentration of hydroxyl groups on the surface and thus have poor dyeing performance. In this case, hydroxyl‐rich nanocellulose (NC) offers a fascinating solution for improving the dyeing properties of PVA fibers. Herein, we developed NC/PVA composite fibers by wet spinning the aqueous mixture of NC and PVA followed with acetalization treatment. Compared with pure PVA fibers, NC/PVA composite fibers had a significant improvement of 36% and 53% in terms of tensile strength and elongation at break when the NC content was 10 wt%, respectively. More importantly, when the NC content reached 20 wt%, the K/S value of the composite fiber was approximately threefold greater in comparison to that of the PVA fiber, indicating that the dyeing performance of NC‐modified composite fibers was greatly improved. This work provides a simple and easy method to possess PVA fibers with excellent dyeing properties and mechanical properties, demonstrating the potential to realize the application of PVA fibers in more practical scenarios.

The Effects of Cross-Linking Agents on the Mechanical Properties of Poly (Methyl Methacrylate) Resin.

Cross-linking agents are incorporated into denture base materials to improve their mechanical properties. This study investigated the effects of various cross-linking agents, with different cross-linking chain lengths and flexibilities, on the flexural strength, impact strength, and surface hardness of polymethyl methacrylate (PMMA). The cross-linking agents used were ethylene glycol dimethacrylate (EGDMA), tetraethylene glycol dimethacrylate (TEGDMA), tetraethylene glycol diacrylate (TEGDA), and polyethylene glycol dimethacrylate (PEGDMA). These agents were added to the methyl methacrylate (MMA) monomer component in concentrations of 5%, 10%, 15%, and 20% by volume and 10% by molecular weight. A total of 630 specimens, comprising 21 groups, were fabricated. Flexural strength and elastic modulus were assessed using a 3-point bending test, impact strength was measured via the Charpy type test, and surface Vickers hardness was determined. Statistical analyses were performed using the Kolmogorov-Smirnov Test, Kruskal-Wallis Test, Mann-Whitney U Test, and ANOVA with post hoc Tamhane test (p ≤ 0.05). No significant increase in flexural strength, elastic modulus, or impact strength was observed in the cross-linking groups compared to conventional PMMA. However, surface hardness values notably decreased with the addition of 5% to 20% PEGDMA. The incorporation of cross-linking agents in concentrations ranging from 5% to 15% led to an improvement in the mechanical properties of PMMA.

The Unique Morphology of Coconut Petiole Fibers Facilitates the Fabrication of Plant Composites with High Impact Performance.

The present work explored alkali-treated coconut petiole fibers (ACPFs) characterization and the effect of fiber loadings on the mechanical properties of poly (lactic acid) (PLA)/ACPF composites for the first time. The physical, mechanical, and interfacial properties, as well as the morphology of the ACPFs were reported. It was found that ACPFs with a density of 0.92 g/cm3 have average tensile strength and tensile modulus equal to 355.77 MPa and 5212.36 MPa. The interfacial strength between ACPFs and PLA was high (14.06 MPa), attributed to the micro-sized holes on the fibers, as established from SEM micrographs. Then composites with varying fiber loadings were fabricated by melt-blending and compression molding. The mechanical (tensile, flexural, and impact) performance of composites was reported. Based on the high interfacial strength between fibers and PLA and the unique "spiral" structure of fibers, the composites reached a high impact strength of 8.2 kJ/m2 and flexural modulus of 6959.70 MPa at 50 wt.%, representing 150% and 50% improvement relative to pure PLA.

Improvement in structural, thermal, charge transport and mechanical properties of poly (methyl methacrylate)/polyindole composites for optoelectronic devices

This study encompasses the synthesis, characterization, optical properties, thermal, mechanical, and electrical characteristics of a series of in situ polymerized poly (methyl methacrylate) (PMMA) with different contents of polyindole (PIN) composites. The formation of composites was characterized by FTIR, UV-visible, XRD, FE-SEM, AFM, DSC and TGA. Tensile testing techniques was used to determine mechanical properties such as tensile strength, modulus, hardness and impact strength of PMMA/PIN. Impedance spectroscopy was used to study the electrical properties of the prepared composites. The interaction between the NH moiety of indole and ester groups of PMMA was established through FTIR. The optical bandgap energy determined from UV spectroscopy shows a declining trend, whereas the refractive index grows significantly with the loading of indole up to 5 wt%. The decrease in broadness and intensity of the XRD peak confirmed the presence of an indole component in the PMMA matrix. The holes in the surface morphology of PMMA was changed into uniformly dispersed particles, confirming the dispersion of PIN in the PMMA matrix. The surface roughness obtained from AFM increases with the addition of PIN to PMMA. DSC measurements show that the glass transition temperature of the polymer increases with the inclusion of the indole moiety. TGA indicates that the addition of PIN has a positive effect on the thermal stability of PMMA/PIN composites. The results of mechanical testing showed an increase in Youngs modulus, tensile strength, and impact strength with the addition of PIN. The AC impedance results show an increase in the dielectric constant and conductivity of PMMA with the PIN addition. PMMA/PIN composites with high tensile strength, conductivity and dielectric constant can be used in the fabrication of optoelectronic devices and EMI shielding.

The Influence of Processing Conditions on the Mechanical Properties of Poly(Acrylonitrile-Butadiene-Styrene)/ Poly(Methyl Methacrylate) (ABS/PMMA) Blends

Poly(methyl methacrylate) (PMMA) can improve the mechanical and optical properties of poly(acrylonitrile-butadiene-styrene) (ABS). The blends of ABS and PMMA are applied to produce electrical enclosures with high requirements for gloss and hardness. Knowledge about the processing conditions that influence the blends of polymers is important to achieve the best material properties. In our research described here, ABS/PMMA blends and their testing samples were separately prepared under various processing conditions based on polymer blending theory. The influence of extrusion (times) and injection (temperatures and pressures) conditions on the mechanical properties and morphologies of the ABS/PMMA blends were investigated. Appropriate processing conditions and optimal mechanical properties of the ABS/PMMA blends were obtained. The blends following extrusion processing twice had better impact strength, tensile properties, and bending properties than those prepared with only one extrusion processing. The blends prepared under injection processing conditions (220 °C, 70 MPa) had better mechanical properties than those prepared under other conditions. Therefore, it was possible to correlate the processing conditions with the evaluated mechanical properties.

Effect of silver nanoparticles on structural, thermal, electrical, and mechanical properties of poly(vinyl alcohol) polymer nanocomposites

AbstractThis paper presents the in‐situ chemical synthesis of silver nanoparticles (AgNPs) with glycerol embedded in poly(vinyl alcohol) (PVA) to synthesize (PVA/AgNPs) polymer nanocomposites with different volume percentages of AgNPs (2, 4, and 6) %v/v. X‐ray diffractometer shows the (200) plane of AgNPs, which appeared at 44.82° in PVA/(2, 4, and 6) %v/v AgNPs films. However, the (111), (220), and (311) planes at 2θ (37.55°, 65.08°, and 77.45°) respectively appeared in PVA with 6%v/v AgNPs only. Fourier transform infrared spectroscopy spectrum of AgNPs shows a COC peak at 1273 cm−1 which is attributed to the stronger affinity of AgNPs on the COC bonds in the PVA matrix. The scanning electron microscope confirmed that all nanoparticles are open‐spherical or near‐spherical in shape. Differential scanning calorimetry shows the decrease in glass transition and melting temperature of pure PVA from 64.62° and 185.54° to 53.09° and 182.35° after the incorporation of AgNPs. Thermogravimetric analysis shows the reduction of thermal stability of PVA/AgNPs films when compared to pure PVA. The electrical conductivity of PVA/AgNPs films increased with the addition of AgNPs. From Mechanical studies, the values of Young's modulus, yield strength, and ultimate tensile strength decreased with increasing AgNPs volume percentage.

Mechanical Properties of Poly(Alkenoate) Cement Modified with Propolis as an Antiseptic.

We assessed the effect of propolis on the antibacterial, mechanical, and adhesive properties of a commercial poly(alkenoate) cement. The cement was modified with various concentrations of propolis, and antibacterial assays were performed against S. mutans by both MTT assays and agar diffusion tests. The compressive, flexural, and adhesive properties were also evaluated. the modified cement showed activity against S. mutans in both assays, although reductions in compressive (from 211.21 to 59.3 MPa) and flexural strength (from 11.1 to 6.2 MPa) were noted with the addition of propolis, while adhesive strength (shear bond strength and a novel pull-out method) showed a statistical difference (p < 0.05). the antiseptic potential of modified material against S. mutans will allow this material to be used in cases in which low mechanical resistance is required (in addition to its anti-inflammatory properties) when using atraumatic restorative techniques, especially in deep cavities.

Synthesis, Characterization and Mechanical Properties of Poly (vinyl acetate)/Boehmite Nanocomposites via Emulsion Polymerization

Synthesis, Characterization and Mechanical Properties of Poly (vinyl acetate)/Boehmite Nanocomposites via Emulsion Polymerization

Effects of FDM parameters and annealing on the mechanical and tribological properties of PEEK

In this paper, the effects of FDM parameters (nozzle temperature, platform temperature, layer thickness, and printing speed) as well as annealing temperature on the mechanical properties of poly(ether ether ketone) (PEEK) were investigated through orthogonal experiments. And the tribological properties of PEEK were also studied before and after annealing. Results show that nozzle temperature and printing speed were main factors affecting the mechanical properties of PEEK, which was optimized to be 440 ℃ and 40 mm/s, respectively. The mechanical strength of PEEK was increased with increasing annealing temperature and reached the maximum at 300 ℃ with the sacrifice of elongation at break, and the ultimate tensile, flexural and compressive strength was increased by 36%, 54% and 21%, respectively. As for the tribo-properties, there appeared a minimum wear rate(1.37 × 10−6mm3/Nm) in 200 °C annealed PEEK when tested in parallel manner, combined influences of annealing and filament orientation were revealed, and appropriate annealing temperature was found to help enhance the formation of uniform and homogeneous transfer films on the counter steel surfaces.

Influence of Monomer Structure, Initiation, and Porosity on Mechanical and Morphological Characteristics of Thiol‐ene PolyHIPEs

AbstractCombining high internal phase emulsion templating with thiol‐ene click chemistry produces porous polymers with high yields and degradable ester linkages. This study compares the influence of the monomer functionalities (tri versus tetra), internal phase volume, and initiation type (photo versus thermal) on the morphological and mechanical properties of poly(high internal phase emulsions) (polyHIPEs). For the synthesis of the polyHIPEs pentaerythritol tetrakis(3‐mercaptopropionate) (PETMP, tetrafunctional), trimethylolpropane tris(3‐mercaptopropionate) (TMPTMP, trifunctional), pentaerythritol tetraacrylate (PETA, tetrafunctional), and trimethylolpropane triacrylate (TMPTA, trifunctional) are used. The main factors influencing the properties of the polyHIPEs are the monomer structures and the internal phase volume, while the initiation type influences the morphology of the trifunctional system (pore size and morphology type) resulting in an interconnected cellular morphology in all cases except in the case of the photopolymerization of the emulsion with 85 vol% of the internal phase. The average pore diameter of the trifunctional system ranges from 8.0 to 27.8 µm, while for the tetrafunctional system it ranges from 8.1 to 12.3 µm. The compression moduli of the trifunctional system range from 0.093 to 0.240 MPa and for the tetrafunctional system they range from 1.906 to 7.670 MPa. The compression moduli decrease with increasing internal phase volume (porosity).