Mechanical Properties Of Poly Research Articles

Effect of Graphene Oxide Localization on Morphology Development and Rheological and Mechanical Properties of Poly(Lactic Acid)/Ethylene Vinyl Alcohol Copolymer Blend Composites: A Comprehensive Study

This study investigates the rheological, morphological, and mechanical properties of melt-processed polylactide/ethylene vinyl alcohol (70PLA/30EVOH) blend composites containing 0.25, 0.5, and 1 wt.% of graphene oxide (GO) nanoplates. Thermodynamic-based suggested the localization of nanoparticles in EVOH, SEM studies showed that the introduction of GO to the blend increased dispersed droplet size, which was attributed to the localization of GO within EVOH, as confirmed by TEM. The rheology results indicated a decrease in the elasticity for the composite containing 0.25 wt.% of GO compared to the neat blend, which was attributed to the sliding effect of the added GO nanoplatelets. However, samples containing higher amounts of GO nanoplatelets exhibited more excellent elasticity than the neat blend. The increased elasticity was suggestively attributed to the dominance of hydrodynamic interactions, the physical network of added nanoplatelets, and polymer/GO interactions over the sliding role of the GO nanoplatelets at higher loadings. In addition, the effect of the order of mixing was investigated, and the premixing of PLA and GO exhibited a decrease in the droplet radius compared to the neat blend. It was ascribed to the localization of GO nanosheets in the PLA and interface, which was confirmed by rheological results and mechanical assessments.

Rheological, thermal, and mechanical properties of poly(butylene succinate) (PBS)/poly(L-lactide) (PLA) fiber biodegradable green composites

Rheological, thermal, and mechanical properties of poly(butylene succinate) (PBS)/poly(L-lactide) (PLA) fiber biodegradable green composites

Effect of chain extension on processability and mechanical properties of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)

AbstractPoly(3‐hydroxybutyrate‐4‐hydroxybutyrate) (P34HB) copolyester is a new type of biodegradable polymer material, but it cannot meet the market requirements because of its poor thermal stability. In this work, P34HB with a low degree of cross‐linking was successfully prepared by incorporating a small amount of a multiple epoxy chain extender, known as Joncryl ADR‐4380 (styrene‐methacrylic acid glycidyl ester copolymer), through reactive extrusion. The rheological properties, thermal stability, thermal behavior, and mechanical properties of the materials were investigated. Fourier transform infrared spectroscopy and gel content test showed that there was a significant chemical interaction between P34HB and ADR4380, and a cross‐linked structure was produced. Compared with pure P34HB, the samples after chain extension showed improved rheological properties, with increased viscosity and melt elasticity due to the formation of a gel network. Thermogravimetric analysis, dynamic time scanning experiment, and melt flow index (MFI) provided strong evidence for the enhanced of thermal stability of P34HB. The onset decomposition temperature of P34HB increased by 13.5°C, and its MFI decreased from 23.30 to around 5 at 170°C, and the complex viscosity remained relatively stable with time after modification. In terms of mechanical properties, the maximum elongation at break increased by 88.08% due to the improvement of toughness.

Glass Transition Temperature and Mechanical Properties of Poly(Ethylene Carbonate)/Organoclay Composites

Poly(ethylene carbonate) (PEC) is a form of aliphatic polycarbonate, a biodegradable polymer made via the copolymerization of carbon dioxide and epoxides. The poor thermal stability and mechanical properties of these aliphatic carbonates are attributed to the carbon structure's flexibility, which restricts their applications. By combining PEC with organoclay CP180, this study addressed the weaknesses of PEC with organoclay addition. A physical blending technique was employed to generate PEC/organoclay composites with a 10-50 wt.% ratio of organoclay. The blended material's thermal characteristics were analyzed using differential scanning calorimetry (DSC), and the mechanical characteristics were measured using a universal tensile machine. The Field Emission Scanning Electron Microscopy (FESEM) analysis determined the blends' morphology. Before the torque value for all curves grew with the addition of CP180 material to the PEC matrix, it became constant. It reached a high value due to the shear-thickening behavior of the PEC matrix with organoclay addition. Tg of PEC increased by more than 7°C by 40 wt.% organoclay addition, as evident in the hindrance of PEC flexibility, significantly increased the toughness of this PEC. From the FESEM images, the formation of large silicate starts to aggregate effectively, lowering the interfacial area between organoclay and PEC as the clay content continues to rise, as shown by 50 wt.% organoclay addition.

Mechanical properties of poly(N‐acryloyl‐glycinamide) hydrogels dependent on initiation number of the polymerization reaction

AbstractHydrogels with polymer networks formed through physical interactions have received attention because of their post‐moldability and self‐healing properties upon physicochemical stimulation. Although hydrogels become fragile without covalent crosslinking, poly(N‐acryloyl‐glycinamide) (PNAGA) hydrogels, which are formed through hydrogen bonding among PNAGA molecules, have recently demonstrated exceptional strain. In this study, we prepared a series of PNAGA hydrogels with different molecular weights and constant weight concentrations of PNAGA. Stress–strain tests demonstrated that higher molecular weights of PNAGA promote extensibility. The swelling ability of the hydrogel also increased with higher molecular weights of PNAGA, suggesting that high molecular weights of PNAGA significantly increase the tolerability of hydrogels to shape change, which opens up new possibilities for developing robust hydrogels without the requirement for cross‐linking. Although different behaviors were not observed with changes in the molecular weight, we achieved hydrogel re‐construction using the PNAGA powder obtained from hydrogels, which demonstrates an advantage of such polymer networks based on hydrogen bonding. Regarding the healing ability of the cut surfaces, hydrogels with a lower molecular weight exhibited higher recoveries, probably owing to the high PNAGA mobility in the hydrogels. Finally, this study elucidates the importance of controlling the molecular weight when developing functional hydrogels.

Poly(ethylene succinate-co-lactic acid) as a Multifunctional Additive for Modulating the Miscibility, Crystallization, and Mechanical Properties of Poly(lactic acid).

Polymer blending offers an effective and economical approach to overcome the performance limitations of poly(lactic acid) (PLA). In this study, a series of copolymers poly(ethylene succinate-co-lactic acid) (PESL) were synthesized, featuring lactic acid (LA) contents that ranged from 20 to 86 wt %. This synthesis involved a one-pot industrial melt polycondensation process using succinic acid (SA), ethylene glycol (EG), and LA, catalyzed by titanium tetraisopropoxide (TTP). The goal was to produce a fully biobased copolymer expected to exhibit partial miscibility with pure poly(lactic acid) (PLA). To assess the capability of PESL copolymers in toughening PLA, we conducted tensile testing on PLA/PESL blends containing 15 wt % PESL. As a result, an elongation at break for the blends with 15 wt % loading of the copolymer PESL72 was directly enhanced to 250% with an ultimate strength of 35 MPa, compared to brittle PLA with less 10% tensile length. The morphological features of interfacial adhesion before and after tensile failure were measured by scanning electron microscopy (SEM). A significant enhancement in the chain mobility of the PLA/PESL blends was further evidenced by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). These findings hold promise for the development of functional packaging materials based on PLA. The proposed copolymer design, which boasts strong industrial feasibility, can serve as a valuable guide for enhancing the toughness of PLA.

Influence of different dimensional nanoparticles on the properties of poly(β-hydroxybutyrate-co-valerate) nanocomposites

Abstract In order to study the effect of nanoparticle dimensions on the thermodynamic properties of PHBV and PHBV blends, one-dimensional cellulose nanocrystals (CNC), two-dimensional graphene, and zero-dimensional hydrophobic nano-silica were selected to regulate the crystallization and mechanical properties of poly(β-hydroxybutyrate-co-valerate) (PHBV) and PHBV blends. The morphology, crystallization process, mechanical property and rheological response of PHBV nanomaterials were analyzed. Experimental results show that the three selected nanomaterials all hinder the crystallization process of PHBV, among which two-dimensional graphene exhibits the most obvious hindrance. At the same time, two-dimensional graphene can improve the tensile strength and impact strength of PHBV. However, in the rheological response of PHBV nanocomposites, zero-dimensional hydrophobic nano-silica and one-dimensional cellulose nanocrystals show more obvious regulatory effects than two-dimensional graphene.

Influence of γ-Irradiation on the Electronic Structure and the Chemical and Mechanical Properties of Poly(hydroxybutyrate-valerate)/Poly(caprolactone) Blends: Insights from Experimental Data and Computational Approaches

In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density functional theory (DFT) and the time-dependent DFT (TD-DFT) methods were used together with a model containing four monomer units to provide an insight into the electronic structure, chemical bonds, and spectroscopic (such as Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis)) properties of PHBV and PCL blend phases, which are critical for predicting and designing new materials with desired properties. We found that an increase in γ-irradiation doses caused splitting instead of crosslinks in the polymer chains, which led to evident deformation and an increase in tensile strength at break of 2.0 to 5.7 MPa for the PHBV/PCL blend. Further, this led to a decrease in crystallinity and proved the occurrence of a more favorable interaction between the blend phases.

Study of antibacterial and mechanical properties of poly(methyl methacrylate‐co‐acrylic acid)/hydroxyapatite biocomposite by using artificial neural network approach

AbstractA novel, promising biocomposite was synthesized through the free radical polymerization method using methyl methacrylate (MMA), acrylic acid (AA), and hydroxyapatite derived from oyster shells (Os‐HA). Fourier transform infrared spectroscopy (FTIR) peaks indicate the conjugation of Os‐HA in the biocomposite. From the TGA analysis, it was observed that a weight loss of nearly 2% is achieved at 210°C, up to 15% at 210 to 420°C, and up to 95% at 420 to 580°C. The SEM image shows the uniform dispersion of the Os‐HA particles and strong interaction with the copolymer matrix. The broad spectrum at 2θ = 14.6° in XRD analysis indicates the amorphous nature of poly(MMA‐co‐AA)/Os‐HA. The higher inhibition zone of the biocomposite is observed at 125 μL against E. coli bacteria. The maximum water absorption is observed at 15 wt% of Os‐HA. The young's modulus gradually increases, while the impact strength decreases up to 20 wt% of Os‐HA. The artificial neural network (ANN) model has been used to assess the optimum values of impact strength, tensile strength, and Young's modulus of the biocomposite material. The correlation factor (R = 0.998) of the ANN model data indicates greater accuracy of the experimental result.

Study of the Effect of Multi-Walled Carbon Nanotubes on the Mechanical Properties of Poly(Vinyl Alcohol)/Polyaniline Blend Film

In this research, poly(vinyl alcohol)/polyaniline blend films were fabricated using solution casting technique with different weight ratios of PANI (2, 4, 6, 8, and 10) wt.%. The results showed that the best ratio of the polymer blend was (92% PVA/8% PANI), based on the electrical conductivity of direct current. The results showed that 8 wt.% PANI possessed the highest conductivity. Then, the composite films were prepared by adding multi-walled carbon nanotubes (MWCNT) to the optimum ratio of the polymer blend as a base material and at different weight ratios (0, 1, 3, 5, 7 wt.%). A tension device was used to examine and characterize the prepared samples. It was found that the addition of MWCNT to PVA/PANI caused an obvious decrease in elongation while there was an increase in tension strength and “Young’s modulus”. Optical microscopy results showed a good picture of the distribution of MWCNT particles for composites up to 1 wt.% MWCNT. But, some aggregations can be observed in films with 3, 5, and 7 wt.% MWCNT content.

Hybrid Radiant Disinfection: Exploring UVC and UVB Sterilization Impact on the Mechanical Characteristics of PLA Materials.

This study explores the impact of disinfection techniques on the mechanical properties of poly(lactic acid) (PLA), a crucial material in the production of medical implants, tissue engineering, orthopedic devices and drug delivery systems, owing to its biocompatibility and ease of manufacturing. The focus is on evaluating the effectiveness of ultraviolet (UV) type C (254 nm wavelength) and the combined use of type C and B (310 nm wavelength) disinfection methods. Fifteen tensile test specimens (ASTM D638) and fifteen compression test specimens (ASTM D695) were utilized to assess PLA's mechanical properties, including yield strength, ultimate strength, and fracture strength. The investigation involved subjecting the specimens to the specified disinfection methods and evaluating these properties both before and after the disinfection process. In the tensile test, a statistically significant difference (p = 0) in yield displacement was observed among the three groups. Additionally, a notable difference (p = 0.047) in fracture displacement was identified between the untreated group and the UVC and UVB combination group. No discernible impact on yield or fracture forces was noted. In the compression test, there was a significant difference (p = 0.04) in yield displacement and a clear difference (p = 0.05) in fracture force between the untreated group and the UVC and UVB combination group. The hybrid combination of UVC and UVB disinfection techniques did not affect yield force in both tensile and compression tests. However, it demonstrated a clear impact on displacement, suggesting its potential as a promising disinfection technique in the medical field.

Controlling the Marine Biodegradation Profile and Mechanical Properties of Poly(ε-caprolactone) with Hydrophobic Water-Responsive Linkages

Controlling the Marine Biodegradation Profile and Mechanical Properties of Poly(ε-caprolactone) with Hydrophobic Water-Responsive Linkages

Investigations on dielectric and mechanical properties of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/single-walled carbon nanotube composites

Investigations on dielectric and mechanical properties of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/single-walled carbon nanotube composites

Improvement of compatibility, thermal stability and mechanical properties of poly (phenylene oxide) (PPO) and liquid crystalline polymer (LCPA950) blends with epoxy containing acrylate rubber (ACM) as a compatibilizer

This paper proposes a new approach for improving the compatibility of liquid crystalline polymers with engineering thermoplastics. To improve compatibility and mechanical performance of poly (phenylene oxide) (PPO)/liquid crystalline polymer (LCP) A950 blends, a third component compatibilizer is incorporated into the processing step. In this work, epoxy containing acrylate rubber (ACM) is used for the compatibilization of PPO/LCPA950 blends through the chemical reaction of epoxy functional groups of the acrylate rubber with terminated carboxylic acids or hydroxyl end groups of the two phases. The compatibilization effect on the properties of PPO/LCPA950 blends is investigated by adjusting the amount of acrylate rubber. Fourier transform infrared (FTIR) spectroscopy and melt-rheological analysis were used to study the compatibilization mechanism of acrylate rubber, and the results demonstrate that acrylate rubber is capable of reacting with PPO/LCPA950 to form a chemical bonding interface. The electron microscopic images revealed a well-compatibilized microstructure of PPO/LCPA950 blends in presence of acrylate rubber with submicron-sized liquid crystalline polymer domains in the continuous poly (phenylene oxide) matrix phase, which could not be detected for immiscible PPO/LCPA950 blend. The dynamic mechanical analysis shows that PPO/LCPA950 blend with acrylate rubber exhibit greater elastic storage moduli. It was observed that blends of PPO/LCPA950 compatible with acrylate rubber showed significant increases in tensile strength as well as notched impact strength. These blends can be used in automotive industry.

Morphology and Mechanical Properties of Poly(vinyl alcohol)/Poly(lactic acid) Blend Films Prepared from Aqueous Dispersions

AbstractIn this study, the preparation of poly(vinyl alcohol) (PVA)/poly(lactic acid) (PLA) blends of different compositions, 100/0, 75/25, 50/50, 25/75, and 0/100, by mixing water solutions of the former and water dispersions of the latter polymer, is reported. Two distinct dispersions of PLA are prepared using a commercial‐grade polyester and two different surfactants, an anionic one and a neutral one. Films of PLA and of the corresponding blends are obtained by simply drying at 60 °C the water dispersions without or with the PVA. The films are characterized by infrared spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscope (SEM) analysis. This evidences an island‐like morphology, with the continuous phase consisting of a PVA rich phase at all compositions except 25/75, for which an inverted phase composition, with a continuous phase made mostly of PLA, is instead found. Voids caused by air bubbles trapped in the initial mixture are observed in particular in the formulations with the anionic surfactant. The trapped bubbles result in premature thermal degradation by thermogravimetric analysis (TGA) and mechanical failure during clamping. Films with the neutral stabilizer are tougher than the bare commercial PLA, with Young modulus and elongation at break depending on the combination of the composition and arrangement of blend phases.

Improvement in Phase Compatibility and Mechanical Properties of Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)/thermoplastic Starch Blends with Citric Acid.

Flexible poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) block copolymer (PLLA-PEG-PLLA) bioplastic has been blended with low-cost thermoplastic starch (TPS) to prepare fully biodegradable bioplastics. However, the mechanical properties of PLLA-PEG-PLLA matrix decrease after the addition of TPS. In this work, citric acid (CA) was used as a compatibilizer to improve the phase compatibility and mechanical properties of PLLA-PEG-PLLA/TPS blends. TPS was first modified with CA (1.5 %wt, 3 %wt, and 4.5%wt) before melt blending with PLLA-PEG-PLLA. The PLLA-PEG-PLLA/modified TPS ratio was constant at 60/40 by weight. CA modification of TPS suppressed the crystallinity and enhanced the thermal stability of the PLLA-PEG-PLLA matrix, as determined through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The compatibility between the dispersed TPS and PLLA-PEG-PLLA phases was improved through modification of TPS with CA, as revealed by the smaller size of the co-continuous TPS phase from scanning electron microscopy (SEM) analysis. Increasing the hydrophilicity of the blends containing modified TPS confirmed the improvement in phase compatibility of the components. From the tensile test, the ultimate tensile strength, elongation at break, and Young's modulus of the blends increased with the CA content. In conclusion, CA showed a promising behavior in improving the phase compatibility and mechanical properties of PLLA-PEG-PLLA/TPS blends. These PLLA-PEG-PLLA/modified TPS blends have potential to be used as flexible bioplastic products.

Optimized PCL/CNF bio-nanocomposites for medical bio-plotted applications: Rheological, structural, and thermomechanical aspects

The use of bioabsorbable and biodegradable composites in the medical field has experienced significant growth. Cellulose nanofibers (CNF) have been employed to reinforce medical-grade poly[ε-caprolactone], enhancing both its load-bearing capacity and stiffness compared to pure polycaprolactone PCL. The manufacturing process involved a series of steps applied to five different grades of PCL/CNF filaments. Initially, melt extrusion and pelletization were performed on the filament, followed by 3D bioplotting to create the specimens. The influence of CNF reinforcement on poly[ε-caprolactone] was evaluated through a range of tests, including rheological, thermomechanical, and in situ micromechanical assessments. To further characterize the samples, Micro-Computed Tomography and Scanning Electron Microscopy fractography were employed for the microstructural and morphological analyses, respectively. The mechanical properties of poly[ε-caprolactone]/CNF composites with 6 wt % CNF content exhibited a 23.8% increase in tensile strength and a 19.1% increase in flexural strength compared to the pure matrix, while also displaying minimal porosity.

Enhancing Dielectric Properties, Thermal Conductivity, and Mechanical Properties of Poly(lactic acid)-Thermoplastic Polyurethane Blend Composites by Using a SiC-BaTiO3 Hybrid Filler.

A composite of polymer blends-thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA)-and BaTiO3-SiC was fabricated. BaTiO3 particles were used to improve the dielectric properties of the composite materials, whereas SiC was used to enhance thermal conductivity without altering the dielectric properties; notably, SiC has a good dielectric constant. The surfaces of the filler particles, BaTiO3 and SiC particles, were activated; BaTiO3 was treated with methylene diphenyl diisocyanate (MDI) and SiC's surface was subjected to calcination and acid treatment, and hybrid fillers were prepared via solution mixing. The surface modifications were verified using Fourier transform infrared spectroscopy (the appearance of OH showed acid treatment of SiC, and the presence of NH, CH2, and OH groups indicated the functionalization of BaTiO3 particles). After the extruded products were cooled and dried, the specimens were fabricated using minimolding. The thermal stability of the final composites showed improvement. The dielectric constant improved relative to the main matrix at constant and variable frequencies, being about fivefold for 40% BaTiO3-SiC-TPU-PLA composites. Upon inclusion of 40 wt.% MDI functionalized BaTiO3-SiC particles, an improvement of 232% in thermal conductivity was attained, in comparison to neat TPU-PLA blends.

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.