| 1. |
- Al-Maqdasi, Zainab, 1986-, et al.
(author)
-
Time-dependent properties of high-density polyethylene with wood/graphene nanoplatelets reinforcement
- 2023
-
In: Polymer Composites. - : John Wiley & Sons. - 0272-8397 .- 1548-0569. ; 44:1, s. 465-479
-
Journal article (peer-reviewed)abstract
- The effect of graphene nanoplatelets (GNPs) on the long-term performance of wood fiber/high-density polyethylene (HDPE) composite is investigated by using short-term creep tests with an efficient, faster data analysis approach. Previously, it was shown that the addition of GNPs at 15 wt% into HDPE reduces the viscoplastic (VP) strain developed during 2 h creep by ~50%. The current study shows that 25 and 40 wt% wood content in HDPE reduce the VP strains developed during 2 h creep time by >75% with no noticeable effect of the increased wood content. However, further addition of GNPs results in more than 90% total reduction in the VP strains. The current study shows that the development of the VP strains in the hybrid composites follows Zapas model. Viscoelastic (VE) response of these composites is nonlinear and thus is described by Schapery's model. Parameters for VP and VE models are obtained from the creep experiments and were validated in a separate loading-unloading test sequence. Results show a very good agreement between experiments and predictions for the studied materials as long as the micro-damage is not present.
|
|
| 2. |
- Alsalmah, Hessa A., et al.
(author)
-
Synthesis and characterization of PEG/CS-AgNO3 polymer nanocomposites for flexible optoelectronic and energy storage applications
- 2024
-
In: Polymer Composites. - : WILEY. - 0272-8397 .- 1548-0569.
-
Journal article (peer-reviewed)abstract
- The Polyethylene glycol (PEG) and Chitosan (CS)/silver nitrate (AgNO3) thin films were prepared by utilizing the casting technique to enhance their optical, dielectric, and electrical properties. Their physicochemical characteristics were investigated using a variety of techniques. The FT-IR study demonstrates that the addition of AgNO3 NPs results in a discernible difference in the intensities and locations of vibrational peaks of all bands, supporting the incorporation of AgNO(3)NPs inside the PEG/CS. The XRD analysis indicates that the peak at 2 theta = 23.1(degrees) broadens and strengthens proportionally with the increase of AgNO3 NPs. This observation suggests that the incorporation of AgNO3 NPs into PEG/CS results in a greater degree of amorphous characteristics compared to the PEG/CS blend. Additionally, when the amount of AgNO3 NPs increases in the PEG/CS, the energy band gap decreases, resulting in the creation of localized states between the valence and conduction bands. These polymer nanocomposite films' electrical conductivity, dielectric constant, and dielectric loss all increased with frequency increased and showed variance for various composite concentrations. These AgNO(3)NPs/PEG/CS films can be promising options for frequency-tunable nanodielectrics, flexible dielectric substrates, and bandgap-regulated materials for upcoming microelectronic, capacitive energy storage, and optoelectronic technologies, according to the experimental results.
|
|
| 3. |
- Hosseini, Seyedehsan, 1994, et al.
(author)
-
Alkyl ketene dimer modification of thermomechanical pulp promotes processability with polypropylene
- 2024
-
In: Polymer Composites. - 1548-0569 .- 0272-8397. ; 45:1, s. 825-835
-
Journal article (peer-reviewed)abstract
- Alkyl ketene dimers (AKDs) are known to efficiently react with cellulose with a dual polarity in their structure: a polar component and a nonpolar component. AKD of three different carbon chain lengths, 4, 10, and 16 carbons have been synthesized, and thermomechanical pulp (TMP) fibers were modified by them. The modification of TMP fibers with AKD resulted in an increased water contact angle, showing the presence of the AKDs on the TMP fibers and a new carbonyl peak in the IR spectra, suggesting modification of the TMP fibers with AKD groups. Calculating the Hansen solubility parameters of AKD and AKD conjugated to TMP in polypropylene (PP) indicates improved compatibility, especially of longer chain AKD and TMP AKD. The rheological studies of the composites showed that the AKD with the longest carbon chain decreases the melt viscosity of the PP-TMP-AKD composite, which combined with the shape and the color of the extruded composite filaments indicates improved flow properties and reduced stress build up during processing. The research findings demonstrate the ability of AKD to enhance the dispersibility and compatibility of natural fibers with PP.
|
|
| 4. |
- Hosseini, Seyedehsan, 1994, et al.
(author)
-
Molybdenum disulphide—A traditional external lubricant that shows interesting interphase properties in pulp-based composites
- 2021
-
In: Polymer Composites. - : Wiley. - 1548-0569 .- 0272-8397. ; 42:9, s. 4884-4896
-
Journal article (peer-reviewed)abstract
- Compression molded composites were prepared through a water-assisted mixing of an aqueous suspension of poly(ethylene-co-acrylic acid), additive, and pulp fibers [thermomechanical pulp (TMP) or dissolving pulp (DP)]. The lubricating additives used were magnesium stearate (MgSt) and molybdenum disulphide (MoS2). The composite materials had dry pulp contents ranging from 30 to 70 wt% and 5 wt% additive relative to the weight of the pulp. The adsorption of the additives onto the fibers was confirmed by scanning electron microscopy and energy dispersive X-ray analysis. DMA showed that MgSt and MoS2 gave similar interphase properties for the TMP samples at all loading contents, but the combination of MgSt and MoS2 improved the overall properties of the DP-based composites. The tensile modulus, at 70 wt% fiber content (TMP or DP), increased compared to the matrix by a factor of 6.3 and 8.1, without lubricants, and by a factor of 8 and 10.7, with lubricants, respectively. The increase in melt viscosity observed for the lubricated samples was greater for the TMP-based samples containing MoS2. At a lubricant content of 5 wt%, in 30 wt% TMP, the MoS2 behaved as both a lubricant and compatibilizer.
|
|
| 5. |
- Kumar, S., et al.
(author)
-
Buckling behavior of non-uniformly heated 3D printed plain and functionally graded nanocomposites
- 2023
-
In: Polymer Composites. - : John Wiley & Sons. - 0272-8397 .- 1548-0569. ; 44, s. 5450-5463
-
Journal article (peer-reviewed)abstract
- The functionalized multi-walled carbon nanotubes (MWCNTs) (0.5–5 wt.%) are compounded with high density polyethylene (HDPE), and, subsequently, used for extruding nanocomposite filaments to fabricate nanocomposites (NCs) and functionally graded nanocomposites (FGNCs) through 3D printing. The 3D printed NCs are investigated for coefficient of thermal expansion (CTE), and buckling under different non-uniform temperature distributions (case-1: left edge heating, case-2: centre heating, and case-3: left and right edge heating). A significant reduction in CTE is observed with MWCNT addition and gradation. The highest reduction in CTE is observed for H5 (5 wt.% of MWCNT in HDPE) NC and H1 ⟶ H3 ⟶ H5 (FGNC-2) among the NCs and the FGNCs. It is noted that Tcr (critical buckling temperature) is highest for case-3 and lowest for case-2. The highest deflection is noticed in case-2, while no significant difference is observed in case-1 and case-3 heating conditions. It is also observed that Tcr increases with gradation and MWCNTs addition. The H5 NC and FGNC-2 exhibited the highest Tcr among the NCs and FGNCs, respectively. The maximum deflection is noticed for HDPE, whereas the minimum deflection is noticed for FGNC-2 and H-5 NC among the tested samples. The results also revealed that Tcr is very sensitive to type of heating. © 2023 Society of Plastics Engineers.
|
|
| 6. |
- Petkov, Valeri Ivanov, et al.
(author)
-
Thermal oxidative aging of satin weave and thin-ply polyimide composites
- 2022
-
In: Polymer Composites. - : John Wiley & Sons. - 0272-8397 .- 1548-0569. ; 43:5, s. 2615-2627
-
Journal article (peer-reviewed)abstract
- The weight loss and damage development of satin weave and thin-ply carbon fiber-reinforced polyimide composites are studied during high temperature (288 and 320°C) aging in air. Two distinct regions are identified in the weight loss measurements—a rapid initial desorption and a subsequent slower weight loss, which is attributed to matrix degradation. The initial desorption stage is modeled by combining material constitutive properties from literature, micro-mechanics and a one-dimensional Fickian diffusion model. Two different damage patterns are observed by using optical microscopy and X-ray computed tomography on specimens before and after aging. Crack clusters form a network in satin weave composites, while edge delaminations are observed in thin-ply laminates, which are known for their enhanced resistance to matrix cracking.
|
|
| 7. |
- Roy, Amit, et al.
(author)
-
Tribological properties of polyimide coating filled with carbon nanotube at elevated temperatures
- 2020
-
In: Polymer Composites. - : John Wiley & Sons. - 0272-8397 .- 1548-0569. ; 41:7, s. 2652-2661
-
Journal article (peer-reviewed)abstract
- This work mainly focuses on the development and characterization of polyimide (PI) based composite coatings filled with multi‐walled carbon nanotubes (MWCNT) on a steel substrate. The tribological properties of PI/MWCNT composite coatings at different temperatures ranging from room temperature (RT) to 200°C were investigated. Also, the influence of MWCNT and thermal & mechanical properties of PI composites coatings were measured. The addition of MWCNT could reduce the friction coefficient as well as wear volume at elevated temperatures. The PI/3MWCNT composites coatings show better wear‐resistant properties as compared to other composites. Also, the PI/MWCNT composites showed improved mechanical properties such as micro‐hardness and nanoindentation. Formation of an organic‐inorganic structure due to the inclusion of MWCNT, enhance the mechanical properties and reduce the thermo‐degradation of composites coatings. The glass transition temperature (Tg) of the PI/MWCNT composites was improved as the MWCNT content increases from 0.1 to 5 wt%.
|
|
| 8. |
- Sonker, Amit Kumar, 1989, et al.
(author)
-
Synergistic effect of crosslinking and dual reinforcement on the thermal and mechanical properties of polyvinyl alcohol
- 2021
-
In: Polymer Composites. - : Wiley. - 1548-0569 .- 0272-8397. ; 42:3, s. 1214-1223
-
Journal article (peer-reviewed)abstract
- We examined the combined effect of crosslinking and dual reinforcement on the thermal and mechanical properties of polyvinyl alcohol (PVA). Glutaric acid (GA) was used as crosslinker while tungsten disulfide nanotubes (WSNT) and carboxylated multiwall carbon nanotubes (f-MWCNT) were used as dual reinforcing agents. Tensile strength and toughness of the hybrid composite, that is, crosslinked PVA reinforced with both f-MWCNT and WSNT, was higher than those of neat PVA, crosslinked PVA, crosslinked PVA reinforced with WSNT and crosslinked PVA reinforced with f-MWCNT. The hybrid composite showed remarkable improvement over neat PVA: tensile strength increased by 138%, Young's modulus increased by 142%, and toughness increased by 246%. Water uptake tendency and thermal stability of the composites were also examined and compared. The advantage of using dual reinforcement was a simultaneous increment in tensile strength and toughness, similar to what is observed in some natural materials like nacre.
|
|
