bluuebunny/crossref_metadata_2025_split huggingface dataset:
Halogenated and Non-Halogenated Flame Retardant Additives in Polypropylene (PP) Homopolymer for Battery Applications
Authors: Rangaprasad R. , Rangan K. , Vasudeo Y.B. 
Published: September 2018

The paper describes how to make PP homopolymer flame retardant through the use of halogenated and halogen-free additives. The paper attempts to capture the intricacies involved in compounding recipe development, physical and mechanical properties and performance aspects during injection moulding of the final article. In a nutshell, the paper describes the end user's experience of flame retardant additives in PP homopolymer from concept to product. The present work was directed towards compound development and the characterization of physical, mechanical, flammability performance and performance during the injection moulding of PP homopolymer. The application identified was injection mouldable battery boxes for applications in the telecom sector. PP compounds were prepared from halogen-based and halogen-free flame retardant (FR) additives, designed to meet V0 at 3.2 mm thickness as per the UL94 test protocol. Flame retardant polypropylene; (FR-PP) is used for “back-up” batteries. These are used in telecommunications and railway units and supply energy immediately in the case of an interruption of normal power supply. The batteries contain sulphuric acid as electrolyte. Experimental work was undertaken to develop FR-PP compounds and investigate the effect of FR additives on critical properties. The effect of FR-additives on the heat sealing properties of battery containers was also investigated. The results show that halogenated FR additives can contribute to the excellent acid resistance of PP. Use of non-halogenated FR additives in PP resulted in compounds having densities close to 1.0 g/cm3, at identical loadings to those used with halogenated FR additives. In comparison, FR-PP compounds based on halogenated FR additives gave densities close to 1.2 g/cm3. The data obtained from this investigation show that both types of FR/PP compounds are suitable for battery box applications made by injection moulding.
Crystallinity of Polypropylene-Silica Ash Composites Affected by the Mixing Conditions – DSC Studies
Authors: Chaudhary D.S. , Jollands M.C. , Cser F. 
Published: September 2018

For particulate polymeric composites, mixing is a crucial step to be optimised; and in the process-control stage, identification of the factors that influence mixing is important for a deeper understanding of the composite mechanical performance. A mixing study of a hydrophobic polymer matrix (polypropylene) filled with a hydrophilic particulate-filler (silica from rice husk ash) was carried out using a batch mixer at a constant filler fraction of 20% (w/w). The study involved varying the mixing-time, screw speed and mixing-chamber temperature used to prepare the composites. Mechanical analysis of the samples showed that the tensile strength and modulus values were dependent on the mixing conditions. Furthermore, DSC studies of the samples revealed that the degree of crystallinity was also affected by the mixing conditions. The observed increase in the tensile strength was attributed to the increased filler-matrix interactions; however, there was difficulty in analysing how the mixing conditions influenced the tensile strength because of a lack of extensive data on filler dispersion. The increase in crystallinity, as affected by mixing conditions, was thought to improve the filler-matrix interaction leading to an increased tensile modulus. Interestingly, samples showed permanent morphological changes after their previous thermal histories were erased, suggesting that there was significant interaction between the silica ash particles and the polymer matrix, even though they are quite incompatible. A statistical analysis based on the tensile data was carried out to optimise the state of mixing. The results indicate that (i) the optimised state of mixing correlated with higher crystallinity and (ii) changes in the parameters of physical mixing might significantly affect the homogeneity and crystallinity, both of which are related to the mechanical performance of the composites. Furthermore, reducing the particle size of the silica ash was also found to increase the crystallinity, which was in turn related to the improved tensile properties of the composites. The investigation attempts to highlight that for apparent incompatible system, homogeneity is very important but it alone cannot explain the moderate filler-matrix interactions and filler bonding characteristics that are known to contribute to improved tensile properties. Somehow, composites mechanical properties are improved by optimising the physical mix-state, and by modifying the particle size but it seems like that the net effect is due to increased interactions. In any case, it is clear that optimisation of interactions can be achieved by obtaining a homogeneous phase.
Recycling of Glass-fibre Reinforced Phenolic Prepreg Waste. Part 2. Milled Prepreg as Functional Filler in PP and PA6
Authors: Gröning Mikael , Hakkarainen Minna , Albertsson Ann-Christine 
Published: September 2018

Phenolic resin impregnated glass-fibre prepreg waste was milled and used as reinforcing filler in polypropylene (PP) and polyamide 6 (PA6). Prepreg was particularly suitable to be used as filler in PA6. The fibres were homogeneously distributed during compounding and the addition of 20 wt% prepreg increased the tensile strength of PA6 by 63%, from 52 MPa to 85 MPa. Milled prepreg alone did not significantly increase the tensile strength of PP. However, if compounded together with maleic anhydride grafted polypropylene (PP-g-MA, Epolene G3003) compatibiliser, prepreg can be used as reinforcing filler in PP as well. Addition of 20 wt% prepreg together with 5 wt% Epolene G3003 increased the tensile strength of PP from 26 MPa to 43 MPa. In order to mill the prepreg for compounding with thermoplastics it has to be cured. A 2 kg batch of prepreg had to be cured for at least 2 hours at 200 °C to prevent the phenolic resin from falling off the glass-fibres. Milling should be performed using screens with holes larger than 3 mm in diameter to reduce the amount of prepreg fibres shorter than 2 mm, as they jam the hopper when feeding the recyclate to the extruder. The initial prepreg fibre length is of little importance to the composite mechanical properties, as the fibres are shortened to approximately the same length during compounding.
Structure and Crystallization Behaviour of Poly(∊-caprolactone)/Clay Intercalated Nanocomposites
Authors: Kiersnowski Adam , Kozak Maciej , Jurga Stefan , Pigłowski Jacek 
Published: September 2018

Nanocomposites of poly(∊-caprolactone)/M-HTAB were obtained by polymerization of caprolactone with various amounts (10, 30, 50 and 64 weight ratio) of montmorillonite organophilized with hexadecyltrimethylammonium bromide (HTAB). The microstructure of nanocomposites was studied by small angle X-ray scattering (SAXS). Additionally, the melting enthalpies (ΔHm), the crystallinities and the half-time of isothermal crystallization were evaluated by differential scanning calorimetry (DSC). As a result of SAXS experiments for the composite PCL/M-HTAB 90/10, in the temperature range from 313 to 283 K, a rapid change in the interlamellar distance from 3.1 nm to 2.72 nm was observed. Similar scattering curves were obtained for the nanocomposite PCL/M-HTAB 70/30. In the composites containing 50% and 64% wt of M-HTAB, the decrease in interlayer distance was less pronounced in the same temperature range (d001 3.15 – 3.2 nm). DSC results clearly showed that the crystallization is divided into two separate processes: primary crystallization in the PCL matrix, and secondary crystallization.
Semi-Interpenetrating Conducting Elastomer Composite Thin Films from Polyaniline
Authors: Sreeja R. , Sharma P.D. , Najidha S. , Jayan S. Remya , Predeep P. 
Published: September 2018

The blending of conducting polyaniline (PANI) with elastomers (natural rubber (NR) and acrylonitrile-butadiene rubber (NBR)) by a wet mixing process has been studied with the goal of fabricating flexible ultra thin conducting films. Good conductive properties were found for NR composite films with 30 wt% of HCl treated PANI and NBR composite films with 20 wt% of HCl treated PANI. There was a gradual decrease in surface resistivity with increasing PANI (HCl) concentration. The UV/VIS spectra indicated the presence of conjugated sequences of conducting polyaniline in the composite films. The FT-IR/ ATR results indicated the compatibility of HCl doped PANI with both NR and NBR and hence better mechanical properties, as indicated by an increase in the Young's modulus. Thus the conducting component acted simultaneously as reinforcement and conductive filler for both matrices. However the NBR composites became harder and more brittle with the increase in PANI concentration. The results have been correlated with swelling measurements confirming the formation of an interpenetrated network, which inhibits rubber solubilization. The method opens up a new technique for preparing stable conductive thin films of PANI using dopants such as HCl.
The Influence of Through-the-Thickness Binder Yarn Count on Fibre Volume Fraction, Crimp and Damage Tolerance within 3D Woven Carbon Fibre Composites
Authors: King R.S. , Stewart G. , McIlhagger A.T. , Quinn J.P. 
Published: September 2018

This paper presents a study into the influence of the Through-The-Thickness (T-T-T) binder yarn count on the fibre volume fraction (Vf), crimp and damage tolerance within 3D woven carbon fibre composites. Three fabrics were woven with varying binder yarn counts; the first had 1x12k binders, the second had 2x6k binders (two individual 6k tows laid on top of one another into the structure to form one tow) and the third had 1x6k binder tows. Dry fabric compress tests conducted on the three 3D woven fabrics showed that a power law can be successful utilised to predict Vf and identify the required pressure to achieve a specific Vf. All three fabrics achieved Vf‘s in the range of 45–47% however the 2x6k binder fabric had higher %CV's compared to the other fabrics. The degree of crimp within the three 3D woven fabrics was shown to be highest within the 1x12k binder fabric followed by the 1x6k binder fabric with the 2x6k binder fabric having the lowest percentage crimp. Compression after Impact (CAI) tests were conducted and showed that impact depth was significantly influenced by impact location on the T-T-T binders with impact depth differences up to 97% observed. It was shown that impact location and depth played no major role in the CAI strength of the composite. CAI strength was observed to be highest within the 2x6 k binder composite followed by the 1x6k binder composite with the 1x12k composite having the lowest CAI values.
Silver Ion Release from Antimicrobial Acrylate Photopolymer Layers
Authors: Damm C. , Münstedt H. 
Published: September 2018

Crosslinked silver-filled acrylate photopolymer layers on polyetheretherketone (PEEK) films were prepared by a heterogeneous photocatalytic polymerisation initiation using silver-coated titanium dioxide as a catalyst material. The silver ion release from 5 μm thick acrylate photopolymer layers was studied as a function of the chemical structure of the polymer matrix. The silver ion release increases with the number of ethoxy groups per monomer unit, although the filler content in all acrylate samples was the same (2.5 wt.% titanium dioxide coated with 1 mol.% elemental Ag). This finding can be explained on the basis of the water uptake of the polymer matrix: silver ions are generated from elemental silver particles only in the presence of water. The maximum water absorption of the photopolymers as well as the diffusion coefficient of water in the polymers increases with the number of hydrophilic ethoxy groups per monomer unit. The silver ion release from the acrylate photopolymer layers is governed by diffusion. The diffusion coefficient of silver ions, however, is at least two orders of magnitude smaller than that of water. This finding suggests that the interactions between silver ions and the polymers and/or the titanium dioxide must be stronger than the interactions between water molecules and the polymers and/or the titanium dioxide because the mobility of a diffusing species decreases if the interactions with the surrounding matrix become stronger. Acrylate photopolymer layers containing at least 6 ethoxy groups per monomer unit release an amount of silver ions of 3 μg*l-1*cm-2 or more per day. This amount is sufficient to eliminate Escherichia coli completely within 24 h.
Effects of Molecular Weight of Polypropylene on the Correlation between Fracture Toughness and Mechanical/Impact Properties of Gfpp Composites
Authors: Ogazi-Onyemaechi Bernard Chukwuemeka , Leong Yew Wei , Nakai Asami , Kotaki Masaya , Hamada Hiroyuki 
Published: September 2018

The accurate prediction of scientific and statistical parameters depends, largely, on the functional correlation between the variables involved, as well as their definite and predictable behaviour around the line of best fit (the regression line). Hence, an accurate and reliable prediction of the fracture toughness and mechanical properties of glass fibre reinforced polypropylene (GFPP) composites is very important in order to prevent sudden failure of components fabricated from them. It also gives the opportunity to save cost on experimentation. Three grades of polypropylene (PP) of different molecular weights (MW) had glass fibre reinforcements each. The incorporation of maleic anhydride grafted PP (MA-g-PP) into the composites was for compatibilisation between the matrix and reinforcements. There was tensile testing on both the un-notched and notched dumbbell samples. The use of J-Integral analysis was to investigate the fracture toughness of the composites. There was an evaluation of the effect of different MW of PP on the fracture toughness and impact properties of the composites. The examination of the morphology of the materials was by (SEM), while charge coupled device (CCD) camera monitored crack propagation behaviour under tensile loading. There was further morphology study to analyse the fibre length distribution and interfacial shear strength of the composites. Investigations revealed that the composite with the lowest MW PP consistently showed better mechanical, impact and fracture toughness properties than those with higher MW PP. It was also observed that incorporating MA-g-PP as compatibilisers had greater interfacial bonding effects, resulting in higher interfacial shear strength in GFPP of lower MW and high melt flow rates than those of higher MW and low melt flow rate. The investigation further revealed that as the MW of PP decreased, the fracture toughness and other mechanical properties increased in a linear correlation. Crack propagation trailed the interface between PP matrix and GF because of weak bonding in the composite with higher MW PP. This study revealed that incorporating MA-g-PP into GFPP composites achieved better properties with PP of lower MW and higher melt flow rate. Hence the mechanical and fracture properties of GFPP depend largely on the MW of the polymer PP matrix. There was a strong linear correlation observed between the MW of PP, fracture toughness and other impact properties thereby making it possible to make a reliable prediction of any property of the composites from another.
Compression and Recovery Behaviour of Polyamide-6 Based Foams
Authors: Izzard V.G. , Hadavinia H. , Morris V.J. , Foot P.J.S. , Wilson L. , Hewson K. 
Published: September 2018

This paper presents experimentally determined compression sets and compression behaviour of two closed-cell, crosslinked foam materials; ZOTEK N B50 (Nylon 6) and ZOTEK N A30 (nylon/polyolefin alloy). This work forms the basis of future investigations into the post-impact behaviour of these foams. Compression set performance was measured at 25.0, 37.5 and 50.0% strain at nine temperatures ranging from −5 to 90 °C. Compression tests at constant strain rates were conducted at four temperatures between 23 to 90 °C. Finally compression tests at 23 °C were repeated at four strain rates between 0.3 and 550 hr−1 to determine strain rate dependency. The Nagy and Williams-Landel-Ferry scaling factor for strain rate and temperature were applied to the experimental results and equations were derived which allowed the performance of the two polyamide based foams to be interpolated over the strain rate and temperature range of study. The required material properties of interest of the base polymers have been assessed and are presented and discussed in relation to the performance of the foam materials.
FT-IR Studies on the Cyclization Reaction of Acrylic Fibres
Authors: Farsani Reza Eslami 
Published: September 2018

In this paper, chemical structure of three different acrylic fibres containing itaconic acid (IA), sodium methallyl sulfonate (SMS) and sodium 2-methyl-2-acrylamidopropane sulfonate (SAMPS) comonomers were studied by Fourier transform infrared (FT-IR) spectroscopy. This study was conducted in order to find the effects of precursor type acrylic fibres on the chemical interaction during the stabilization and on the properties of fabricated carbon fibres. The results of FT-IR show that the peaks related to C≡N bonds in acrylic fibres containing IA comonomer were completely removed during stabilization, while the peaks in SAMPS and SMS were just reduced. Also, the peak related to CH2 bond for acrylic fibres containing IA comonomer was reduced sharply in comparison with the other two fibres. These changes show that cyclization of nitrile groups and stabilization reactions in acrylic fibres having IA comonomer were completed. These reactions increase the tensile strength of carbon fibres produced from this material in comparison with other carbon fibres produced from acrylic fibres containing SAMPS and SMS.
A Study on Degradation of Composite Material PBS/PCL
Authors: Huang Jitao , Cui Chunna , Yan Guiyang , Huang Jianhua , Zhang Min 
Published: September 2018

A systematic study on the degradation and mechanism of composite materials based on polybutylenes succinate/ polycaprolactone (PBS/PCL) was conducted by putting composites of different ratios into the local soil culture solution and cured compost culture solution to observe the microbial reaction. The surface morphologies, crystallinities, and structures of the composites before and after degradation were characterized by FTIR, XRD, and SEM. The results revealed that the original functional groups of the composites were retained perfectly after the mixing and fusing of PBS and PCL, and hydrogen bonds were formed between these two phases. The composite based on PBS and PCL degraded well in the compost culture solution. The weight of this composite was reduced by 32.67% after 60 d. Degradation of the composite in the soil culture solution was indicated by a weight loss up to 8.76%. PCL degraded much faster than PBS did, while the PBS/PCL composite degraded even faster. Crystallinity was improved after degradation, and the non-crystalline area degraded first. The viscosity analysis showed that the degradation of the composite was achieved by the simultaneous processes of breaking big molecules into small molecules and by the degradation of small molecules. Biodegradable and environmental friendly PBS that belongs to aliphatic series polyester is one of the most promising environmental-friendly and biodegradable polymer materials; PCL is a kind of thermal plastic crystalline polyester with good bio-degradability, drug permeability, and biocompatibility. Meanwhile, the raw materials for PCL preparation are cost-effective and accessible. Due to the wide application of bio-degradable materials, the relationship between the degrading rate and the molecule design of bio-degradable material is becoming a key research topic in the area of biodegradable materials1–10. Zhang et al. studied the relationship between the chemical structure of PBS and its degradable structure11–16; the influences of microorganism quantity, humidity, temperature, metal ions, and pH on the degradable property were also studied17–21. In addition to the factors mentioned above22–26, adding other materials also greatly influences degradation performance. In practical applications, the mechanical properties of biodegradable materials are not as good as conventional plastics; the uncontrollable degradation rate of the biodegradable materials is another issue that prevents their wider promotion. In this project, PBS/PCL composites of different ratios were prepared. Good mechanical properties and good biodegradability were expected for these composites. A systematic study on the degradation of these composites is presented, which provides good reference for the controllable application of biodegradable plastics. Furthermore, the degradation mechanism of the composites is rationally inferred, which is well supported by reported data. This study facilitates further research on the controlling of degrading rate of PBS/PCL.
Experimental Verification of Lamb Wave Identification of Delamination Defects through Covariance of Energy Change
Authors: Yang Mijia , Bruhschwein Taylor 
Published: September 2018

Delamination is currently a difficultly-detectable form of damage in composite laminate materials. This paper experimentally validates an innovative method that more easily detects delamination damage within composite materials through the covariance of energy change. Lamb waves were introduced and recorded through an actuator and sensors made of piezoelectric material. The data was then analyzed through the Fast Fourier Transform (FFT). Using the data from FFT, the idea of covariance of energy change was suggested to correlate with defect characteristics. By comparing the covariance of energy change in beams with different delamination sizes and depths, correlations between the covariance of energy loss and defect characteristics were developed. With these correlations, the severity of these damages was quantified.
Upper arm basilic vein elevation as a solution for forearm ulnar-basilic arteriovenous fistulae with cannulation problems
Authors: Mallios Alexandros , Jennings William , Costanzo Alessandro , Boura Benoit , Combes Myriam 
Published: September 2018

Background: Ulnar-basilic arteriovenous fistula is an alternative option when a radiocephalic arteriovenous fistula is not feasible. We review our technique of basilic vein transposition in the upper arm for difficult to puncture forearm ulnar-basilic non-transposed arteriovenous fistulae. Technical note: Three patients were referred for forearm ulnar-basilic arteriovenous fistulae with difficult cannulation where the forearm basilic vein was left in situ (non-transposed). Surgeon performed ultrasound examination confirmed a patent arteriovenous fistula with adequate diameter and flow, draining to the basilic vein in the forearm and into the upper arm. Recurrent new and resolving hematomas were present surrounding the forearm basilic vein resulting from difficult cannulation issues and problems maintaining needle position due the posterior-medial ulnar-basilic arteriovenous fistula position and mobility of the non-transposed forearm basilic vein. A basilic vein transposition elevation procedure was performed in the upper arm starting at the level of the elbow to a few centimeters below the axilla. Branches of the dilated basilic vein were ligated, the median cutaneous nerve was preserved, and the vein was elevated from its native position to a superficial and anterior location. Although difficult, dialysis access had been continued in the forearm during a brief period and none required catheter placement. Reliable dialysis access was successfully initiated using the newly transposed basilic vein in the upper arm 3–4 weeks after the procedure, maintaining arterial inflow based on the original ulnar-basilic arteriovenous fistula anastomosis at the wrist. None of the patients required further interventions with follow-up of 8, 15, and 22 months.