Polymer Journals

Polymers and Polymer Composites

Logged into APC, CP, IPSAT, PPC, PRR, RRR & PRPRT.

Back  Search



Title: Influence of fibre treatment on the characteristics of buriti and ramie polyester composites
Page Range: p.247-256
Author(s): Lavoratti A; Daiane Romanzini; Amico S C; Zattera A J
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Natural fibres have recently attracted interest due to their beneficial characteristics such as low cost and biodegradability. This work aims to characterise in natura, washed and alkali-treated buriti and ramie fibres and to evaluate the influence of the chemical treatments in the mechanical and dynamic mechanical performances of their composites produced by resin transfer moulding (RTM). Fibres were cut to 45 mm in length, washed in distilled water and treated with 2, 5 and 10 wt.% sodium hydroxide solutions. The chemical composition of the washed fibres was not altered. The 2 wt.% NaOH solution increased the flexural strength of polyester/ramie composites by 70%, and improved the impact performance of the alkali-treated polyester/buriti composites. The polyester/ramie composites exhibited superior dynamic mechanical properties and better adhesion at the fibre/matrix interface, and the morphology of buriti limited the fibre wettability during the RTM processing. 29 Refs.

Title: Corona treatment of filled dual-polymer dispersion coatings: surface properties and grease resistance
Page Range: p.257-266
Author(s): Sami-Seppo Ovaska; Geydt P; Ringaudas Rinkunas; Tadeusz Lozovski; Robertas Maldzius; Jonas Sidaravicius; Osterberg M; Leena-Sisko Johansson; Kaj Backfolk
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Dispersion coating layers consisting of hydroxypropylated starch, 0-30 pph of barrier-grade talc and 0-10 pph of styrene-butadiene latex were subjected to both positive and negative direct-current corona treatments utilising a specially developed dynamic treatment unit. The effects of the surface composition (barrier coating) on the response to the direct current corona treatment were evaluated by measuring contact angles and determining the surface energy. The effects of corona treatment on the properties of the barrier coating were further determined by measuring the contact angle of rapeseed oil and the grease resistance. It was found that the grease resistance of the corona-treated barrier coatings was substantially lower than that of untreated samples, which was ascribed to holes caused by corona discharge strike-through and to chemical changes on the treated surfaces. The corona treatment lowered the surface energy of the coatings, as indicated by an increase in the contact angles of water and rapeseed oil. Changes in the dispersion part of the surface energy were recorded, particularly after positive treatment voltage, whereas a negative discharge led to greater changes in the polar part of the surface energy. X-ray photoelectron spectroscopy (XPS) tests revealed an increase in the proportion of talc at the surface after corona treatment, which indicates a migration caused by the applied electric field. The peak force tapping mode of an atomic force microscope revealed moderate topographical changes in the coatings and a decrease in surface elasticity, supporting the migration of talc particles. In addition, significant changes in the physicochemical properties of the untreated reverse side were observed. 39 Refs.

Title: Thermal stability of optically transparent alpha-zirconium phosphate/poly(methyl methacrylate) nanocomposites with high particle loading
Page Range: p.267-272
Author(s): Hatanaka L C; Diaz A; Qingsheng Wang; Zhengdong Cheng; Sam Mannan M
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Polymeric nanocomposites have gained attention over the past few decades for their enhanced thermal stability and degradation. However, the reactions involved in a polymer nanocomposite can vary significantly from system to system, making it necessary to investigate novel nanofillers in search for more effective materials. Nanocomposites comprised of alpha-zirconium phosphate (ZrP) nanosheets in poly (methyl methacrylate) (PMMA) were prepared with a wide range of nanoparticle loadings (0, 5, 10, and 30 wt.% ZrP in PMMA). The ZrP nanocomposites were characterised using UV-visible spectroscopy (UV-vis), x-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Nanocomposites were well dispersed and optically transparent as shown by XRD and UV-vis. However in the UV region, transparent ZrP nanocomposites possessed excellent UV scattering properties, significantly reducing the transmittance of UV light, while remaining transparent to the visual spectrum. Thermal stability studies using TGA and DTG showed the peak mass loss rate (PMLR) was reduced by 10% and simultaneously shifted to higher temperatures by 41 deg C. Since the nanocomposites in this work cover such a large range of ZrP loadings, large amounts of high temperature residuals were encountered after TGA studies, indicating that the high loading ZrP nanocomposites are largely noncombustible. In addition, DSC studies showed that ZrP content does affect the glass transition temperature, but not enough to limit the application in which ZrP nanocomposites could be used. These results point to ZrP nanocomposites being useful as polymer replacements, behaving like polymers until the event of a fire, in which case they are largely noncombustible. 21 Refs.

Title: Cellulose nanofibers-graphene nanoplatelets hybrids nanofillers as high-performance multifunctional reinforcements in epoxy composites
Page Range: p.273-284
Author(s): Md Nuruddin; Mahesh Hosur; Raju Gupta; Gaurav Hosur; Tcherbi-Narteh A; Shaik Jeelani
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
The objective of this study was to fabricate epoxy polymer composites modified with cellulose nanofibres (CNFs) and graphene nanoplatelets (GNPs) binary filler materials. Individual (0.2 wt.% GNPs or 2 wt.% CNFs) and binary nanofillers (mixture of 0.5 wt.% CNFs and 0.1% GNPs) were incorporated into an epoxy matrix system to investigate the synergistic effect of nanofillers on composites properties. Dynamic mechanical analysis (DMA) and three point bend tests were carried out to investigate the viscoelastic and flexural properties of neat epoxy and nanofiller-reinforced nanocomposites. Incorporation of binary nanofillers resulted in better flexure strength, modulus and storage modulus although there was no significance change in glass transition temperature (Tg). FTIR analysis was carried out to study the probable reaction mechanism of epoxy polymer with binary nanofillers. SEM images of the fracture surface of the samples revealed rougher failure surfaces for nanophased samples. 36 Refs.

Title: Effect of rubber content on fatigue crack growth rate under mode I loading
Page Range: p.285-288
Author(s): Makoto Imanaka; Hiroshi Asano
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Rubber-modified adhesives have attracted particular interest recently, owing to their property of dramatically increasing the fracture toughness of adhesively-bonded joints. In many cases, these joints are exposed to cyclic loads, and hence an understanding of the fatigue mechanisms is of paramount importance. This study was conducted to characterise the rubber content-dependent behaviour of rubber-modified epoxy adhesive under cyclic loading. Fatigue crack growth rates under mode I loading were measured using adhesively bonded double cantilever beam specimens with rubber contents of 0, 5 and 14 wt.%. As a result, in the Paris region, an increase in rubber content reduced the fatigue crack growth rate. Similarly to the Paris region, the fatigue threshold for 5 wt.% was greater than that for 0 wt.%; however, the fatigue threshold of joints with 14 wt.% rubber content was nearly equal to those with 5 wt.%. 8 Refs.

Title: Experimental study of in-plane mechanical properties of carbon fibre woven composite at different strain rates
Page Range: p.289-298
Author(s): Jiahai Lu; Ping Zhu; Qinghui Ji; Zhang Cheng
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Carbon fibre woven composite has been increasingly employed in engineering applications undergoing complex loading conditions. For effective use of composite material in dynamic applications, it is essential to fully understand the mechanical behaviour of composite at different strain rates. In the present study, both in-plane tensile and compressive experiments loaded at 0 degree axial direction and 45 degree off-axial direction of a TC33 carbon fibre woven composite were investigated over the strain rate range from 0.001 to 1000 s-1. High strain rate tests were carried out using Split Hopkinson Pressure and Tensile Bar apparatus respectively. The results indicated that the in-plane mechanical properties and failure patterns were strain rate sensitive under both tensile and compressive loadings. The mechanical properties, failure patterns and strain rate effect also showed highly direction dependent and tension/compression asymmetric characteristic within the considered strain rate range. For higher strain rate sensitivity under compression than that under tension, the asymmetry of mechanical properties was less obvious with the increase of strain rate. Finally, two phenomenal models were proposed to quantitatively fit the relationship between strength property and strain rate. 23 Refs.

Title: High density polyethylene/pistachio shell flour/nanoclay composites - effect of accelerated weathering conditions on mechanical properties, relative brightness and total colour change
Page Range: p.299-308
Author(s): Abedini Najafabadi M A; Nouri Khorasani S; Moftakharian Esfahani J
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
This study investigates the effect of the addition of nanoclay (Cloisite 20A) on some mechanical properties, % relative brightness ((DELTA)Lrel) and total colour change ((DELTA)Eab) of high density polyethylene (HDPE)/pistachio shell flour (PSF) composites when exposed to accelerated weathering conditions. X-ray diffraction (XRD) patterns of samples containing 3 and 6 per hundred composite (phc) of nanoclay indicated partial exfoliation and intercalation. The tensile modulus and tensile strength of HDPE/PSF composites (without nanoclay) decreased when the exposure time increased to 1500 h, while the tensile modulus and tensile strength increased. For samples with nanoclay, (DELTA)Lrel and (DELTA)Eab increased upon accelerated weathering conditions up to 500 h, and thereafter remained constant. But results show that (DELTA)Lrel and (DELTA)Eab increased significantly upon accelerated weathering exposure in HDPE/PSF samples up to 1500 h. Scanning electron microscopy (SEM) results after 1500 h exposure to weathering condition showed signs of the presence of cracks in samples without nanoclay, unlike the samples with nanoclay. 15 Refs.

Title: Effect of Na+ and Ca2+ on the thermal degradation of carboxymethylcellulose in air
Page Range: p.309-314
Author(s): Liwen Tan; Ran Shi; Quan Ji; Bingbing Wang; Fengyu Quan; Yanzhi Xia
File size:
Download the pdf (subscribers only)
Buy the pdf (non-subscribers)
Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 25
Issue No: No.4

Abstract
Carboxymethylcellulose (CMC), including the acid form (CMC-H) and salt forms (CMC-Na, CMC-Ca), were prepared for the survey of thermal degradation and the CMC-H was obtained by acidifying CMC-Na with HCl. An online-coupled thermogravimetric (TG)-FTIR evolved gas analysis instrument was used to identify and monitor the evolution of gaseous products during the thermal degradation of CMC in air. The thermal degradation characteristics of CMC-H and salt forms CMC-Na, CMC-Ca of carboxymethylcellulose were compared to determine the effect of Na+ and Ca2+ counter-ions on CMC thermal degradation in air. From the TG and DTG curves, thermal degradation of the samples occurred in three stages. During the second stage (200-410 deg C) major degradation occurred, accompanied by a large weight loss. The 3D FTIR absorbance spectra and Gram-Schmidt curves of the evolved gases were obtained. In compounds CMC-Na and CMC-Ca, the initial degradation temperature is higher, the rate of CMC degradation increases, and the weight loss in the temperature range 200-410 deg C decreases. These samples also catalyse the stable intermediate products in the temperature range 410-600 deg C. 17 Refs.

%>