International Journal of Polymer Analysis and Characterization最新文献

In this study, four distinct composite samples (Samples A, B, C, and D) were fabricated using varying compositions of biochar, rice bran, coconut coir, and epoxy matrix. Sample A, serving as the baseline with 90% epoxy and 10% biochar, exhibited moderate mechanical properties. Sample B, with 80% epoxy and 20% biochar, demonstrated significantly higher tensile and flexural modulus values, indicative of improved stiffness. Sample C, incorporating 10% rice bran alongside 80% epoxy and 10% biochar, displayed reduced mechanical properties compared to Sample B, potentially due to the lower strength of rice bran particles. Sample D, comprising 80% epoxy, 10% biochar, and 5% coconut coir, demonstrated weaker tensile properties but higher flexural modulus, suggesting enhanced resistance to bending forces. Mechanical testing, water absorption analysis, Fourier Transform Infrared (FTIR) spectroscopy, and SEM imaging provided comprehensive insights into the mechanical and chemical characteristics of the composites, underscoring their potential for diverse applications in sustainable materials development.

This study investigates the impact of the ion beam on the properties of composite PEO/NiO, which was fabricated using the solution casting method and applied in advanced dielectric applications. The samples were exposed to ion beam at different fluencies (5 × 10¹⁶, 10 × 10¹⁶, and 15 × 10¹⁶ ions/cm²) using cold cathode ion source. The structure of the pure and treated PEO/NiO films was studied using the XRD technique, which demonstrated the successful fabrication of the composite PEO/NiO. Moreover, the morphological changes were analyzed by SEM, which indicates the homogeneous distribution of NiO in PEO. Furthermore, the dielectric characteristics of PEO/NiO films were tested at a frequency range of 40–10⁶ Hz. The dielectric constant enhanced from 22.8 for PEO/NiO to 128.5 for the irradiated 15 × 10¹⁶ ions/cm², and the energy density enhanced from 1.1x10⁻⁴ to 5.6x10⁻⁴ J/m³. The results demonstrate that the irradiated PEO/NiO composite exhibits novel dielectric properties, allowing the use of the irradiated PEO/NiO composite in different devices as super-capacitors and batteries.

A comprehensive study has been carried out to understand the details of structural modifications of polyallyl diglycol carbonate (PADC) polymer under the effects of different external factors. Synergistic effect of heat treatment with radiation on the polymer structure was studied. Incorporation of a neutral chromophore to understand the structural changes was attempted. Theoretical simulations were applied to get insight into the detailed aspects of structural modifications. Diverse techniques were used to characterize the samples and compare with the results of simulation studies.

Biopolymer electrolytes based on methyl cellulose (MC) and sodium bromide(NaBr) have been prepared through solvent casting technique. Both the concentrations of MC and NaBr are varied. The prepared biopolymer electrolytes have been subjected to AC impedance and UV-Vis spectroscopic techniques. The ionic conductivity reached a maximum value of 4.84 × 10⁻⁸ Scm⁻¹ for 0.8 g of MC and 0.2 g of NaBr. UV studies revealed that low direct and indirect band gaps have been observed for the maximum ionic conducting sample. Other optical parameters, such as refractive index, extinction coefficient, skin depth, and optical conductivity, have been estimated. The single-oscillator energy (E o) and dispersion energy (E d) for all the prepared biopolymer electrolyte samples were calculated with the help of Wemple and DiDomenico single oscillator model. The higher-order non-linear susceptibility values were also calculated. Polymer electrolytes are found to be suitable for optical and electronic devices.

In this work, cement kiln dust (CKD) will be studied as an unconventional filler for ethylene-propylene-diene terpolymer (EPDM) rubber as an alternative to silica, which is widely used as filler for many types of rubber. (EPDM)/CKD rubber composites were fabricated using ionizing radiation. EPDM rubber was blended with different portions of cement-kiln dust 5, 10, 15, 20, 25, and 30 phr (phr = parts per hundred rubber). The prepared composites were cured by exposing to different doses of gamma rays up to 150 kGy to enhance the crosslinking of the EPDM rubber. The thermo-mechanical properties of the EPDM/CKD and EPDM/Si composites were investigated as a function of irradiation dose. The results showed a significant improvement in elongation and tensile strength by incorporating cement dust into EPDM rubber up to 20 phr, which is not significantly different from composites incorporated with silica. Gamma irradiation significantly improved the properties of all formulations.

Polyurethane acrylates (PUA) are commonly used as leather finishing agents because of their excellent film-forming, mechanical and abrasion resistance properties. In this study, silicone-modified polyether-based waterborne polyurethane acrylate (WPUA) was synthesized as an environmentally friendly leather finishing agent. The effects of different soft segments on the properties of WPUA were investigated by tensile strength, water absorption, thermogravimetry (TG), derivative thermogravimetry (DTG), and water contact angle tests. The results showed that the WPUA synthesized with PTMG 2000 as the soft segment had higher elongation at break, lower water absorption, and a larger water contact angle. The effect of different mass percentages of silicone on the properties ofpolytetramethylene oxide (WPUA) was investigated by scanning electron microscope (SEM), particle size, zeta potential, Fourier transform infrared spectroscopy (FT-IR), water contact angle, folding resistance, and mechanical properties. It was found that the hydrophobic, tensile, and folding resistance properties of the waterborne leather finishing agent were best when the silicone content was 5 wt%. What’s more, the synthesized silicone-modified polyether-type waterborne polyurethanes, with excellent comprehensive performance, have great potential for industrial application in leather finishing agents.

This study presents the development of a series of biobased polyesteramides, labeled as PEAF_1–3, via a greener approach, from bisfuranic diamine and commercially available aliphatic diesters of varied chain lengths. The resulting polymers showed reasonable molar masses, in accordance with inherent viscosities ranging between 0.19 and 0.35 dL/g. Evaluation of their thermal properties by thermogravimetric analysis and differential scanning calorimetry showcased excellent thermal stability (T d_,max ≥ 335 °C), amorphous character and low glass transition temperature (T g) decreased with the increasing chain length. Moreover, notable finding was the exceptional stability of these polyesteramides against both hydrolytic and oxidative degradation processes. This resistance underscores their potential as highly stable materials, making them promising for various applications where durability and resistance to degradation are crucial.

The research aim is to develop pure epoxy composites (PEC), PTL-reinforced epoxy composites (PTLEC), PTL-loaded and E-glass fiber- incorporated epoxy composites (PTLEIEC), and PTL- and E-glass fabric and graphene oxide-incorporated epoxy composites (PTLEIEGO) were fabricated through an open molding hand layup technique, and structural, mechanical, and thermal stability were carried out and results were compared. Functional groups such as OH, -C-H, C=O, C=C, and C-OH, were found in PTL. Similarly, the OH, C-H, Si-O-Si, C=O, and C-H present in the PTLEIEGO composites were found through Fourier transform infrared spectroscopy (FTIR). The crystal plane orientations (110) and (220) in the PTLEIEGO composites were found through XRD. The surface morphology and elemental compositions of PTLEIEGO composites were found through field emissions electron microscopy (FESEM) and found the presence of different organic and inorganic elemental compositions such as C, O, Si, Ca, Zn, K, and Br as 77.85, 20.78, 0.33, 0.45, 0.05, 0.05, and 0.50 wt.% through energy dispersive X-ray (EDX) spectroscopy. The DSC and TGA were carried out and found the thermal stability of the composites and the onset melting temperature was found to 353.1˚ C. The maximum tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 1.25 MPa, 25 ± 0.5 MPa, 55 ± 0.5 MPa, 93 ± 0.5 MPa, and 120 ± 0.5 MPa as per ASTM D 638. The tensile strength was improved from 1.25 MPa for PTL to 120 ± 0.5 MPa for PTLEIEGO. The FEM results revealed a minimum error of 0 % and a maximum error of 21.38 % compared to the experimental results. The maximum shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 55 ± 0.5 SHN, 59 ± 0.5 SHN, 76.1 ± 0.5 SHN, and 81.4 ± 0.5 SHN, respectively, as per ASTM D2240. The flexural strengths of PEC, PTLEC, PTLEIEC, and PTLEIGO composites were found to be 37 ± 0.5 MPa, 43 ± 0.5 MPa, 94 ± 0.5 MPa, and 131 ± 0.5 MPa, respectively, as per ASTM D 790. The new composites would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands.Highlights

1. The tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO were found to be 1.25, 25 ± 0.5, 55 ± 0.5, 93 ± 0.5, and 120 ± 0.5 MPa, respectively.

2. The tensile strength of the experimental results was compared with FEM results.

3. The shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIGO was determined to be 55 ± 0.5, 59 ± 0.5, 76.1 ± 0.5, and 81. 4 ± 0.5 SHN, respectively.

4. The novel composite would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands.

Poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) exhibit valuable mechanical properties like high stiffness and tensile strength but are sensitive to processing parameters. The influence of these parameters was evaluated by measuring the variation of melt viscosity during processing. For all experiments, in the absence of chain extenders, the decrease in melt viscosity clearly showed the degradation of polymers during processing. This is more pronounced for PHBV than PLA. In order to compensate for the degradation and, if possible, improve the melt strength of these bio-based polymers, two chain extenders have been evaluated: dicumyl peroxide (DCP) and a polymeric epoxy acrylate chain extender (Joncryl^® ADR 4400). DCP reacts quickly with PLA and PHBV, while the epoxy-acrylate chain extender shows slower kinetics. For the PLA, with both investigated chain extenders, an increase in the molecular weight as compared with the virgin polymer and eventually the apparition of an insoluble fraction due to branching and crosslinking are observed. In the case of PHBV, the degradation is compensated by using DCP, requiring short processing times. No significant increase in molecular weight was observed when using the polymeric epoxy acrylate chain extender, requiring longer residence times, although the apparition of a gel fraction suggests the presence of branching and crosslinking.

Two series of unsymmetrical hybrid benzoxazines were separately synthesized using combinations of natural bio-phenolic materials, namely cardanol (C) with eugenol (E), vanillin (V), and guaiacol (G) using diaminodiphenylmethane (ddm)/diaminodiphenyl ether (dde) through the well-known Mannich reaction. The synthesized hybrid benzoxazines have a cure temperature between 229 °C and 269 °C. Compared to previous synthesized benzoxazines, vanillin-based benzoxazines (C-dde-V and C-ddm-V) have a lower cure temperature. TGA results show that poly(C-ddm-V) and poly(C-dde-V), two hybrid polybenzoxazines, have superior thermal stability than the other hybrid polybenzoxazines. In order to develop polybenzoxazine composites, different wt% of GPTMS functionalized vermiculite was incorporated with poly(C-ddm-V). The properties of these composites were examined and contrasted with those of a neat matrix. The hybrid polybenzoxazines and composites water contact angle values vary from 136° to 144°, suggesting that all of the hybrid polybenzoxazines and composites have good hydrophobic behavior. On increasing the concentration of vermiculite, the dielectric constant value significantly decreased to a low dielectric constant.