bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fabrication and Progress of Hollow Structures
Authors: Cao Shunsheng , Chen Juanrong , Hu Jie , Yuan Xinhua
Published: September 2018

The fabrication of hollow particles is one of the fastest-growing fields of materials research, owing to their potential applications in catalysis, chromatography, separation, coatings, protection of bioactive agents, microelectronics and electrooptics. As reported in recent studies, a variety of chemical and physicochemical methods have been employed to prepare hollow spheres with hierarchical and well-defined morphologies. For this, a basic understanding of the mechanism and recent advances in the fabrication of hollow spheres is discussed, along with outstanding challenges, issues, and potentially future opportunities. Evidently, it will enable the development in the fabrication of hollow particles with unique and tailored properties.
Degradation and Dynamic Properties of Poly(amide-co-imide)/Carbon Nanotube Composite Films
Authors: Lee Seung Hwan , Choi Sheong Hyun , Kim Seong Yun , Choi Jin Il , Lee Jae Rock , Youn Jae Ryoun
Published: September 2018

Poly(amide-imide) (PAI)/carbon nanotube (CNT) composite films were investigated through FT-IR spectroscopy, TGA, and DMTA measurements in order to understand the interrelationships of surface modification of CNTs, thermal imidization time, and thermal stability after they were prepared by solution mixing. Thermal stability and glass transition temperature were significantly improved when the PAI/CNT nanocomposites were filled with hydrogen peroxide treated CNTs (p-CNT) because the dispersion of p-CNTs and interfacial bonding between p-CNT particles and PAI molecules were improved. The imidization time of the PAI/p-CNT composite film needed for sufficient imidization reaction was reduced by about 3 hours compared with that of the pure PAI film, because p-CNTs have higher thermal conductivity than the pure PAI resin. They also showed the highest glass transition temperature among all PAI/CNT composites since p-CNTs have many hydrophilic functional groups which yield strong interaction with PAI molecules. It was found that the thermal imidization depended on the network structure which was generated by the crosslinking reaction and surface modification of CNTs.
Studies on VARTM Forming Z-Stitched Foam Core Sandwich Composites
Authors: Wang Shaokai , Li Min , Gu Yizhuo , Zhang Zuoguang
Published: September 2018

Z-stitched foam core sandwich composite is a newly developed structure with through-thickness load-bearing pillars embedded by a stitching technique. In this paper, large-tow glass fibre stitches and fire-resistant phenolic resin were creatively used to fabricate this kind of sandwich composite, which possessed outstanding properties including fire resistance, debonding resistance and high flatwise compressive strength. Vacuum-assisted resin transfer moulding (VARTM) was conducted for processing. The effects of process conditions on key structural parameters of the z-stitched foam core sandwich composite were investigated, including the dimensions of the pillar, the fibre volume fraction of the facesheet as well as the porosity of the pillar. The results show that macroscopic void defects tend to be formed at the joints between the pillars and the top facesheet if air is trapped in the system. The cross sectional areas of the pillars are all larger than the suture needles due to damage of foam cells in the vicinity during stitching process, which is caused by the brittleness of the phenolic resin. Moreover, the dimensions of the pillar could be affected by the vacuum pressure and the pressure gradient, even resulting in local resin-rich area around pillar. In order to optimize the manufacturing quality of this sandwich composite, a small linear density of stitches and a long enough action time of the vacuum process are both very helpful.
Mechanical Properties of Unplasticised PVC (PVC-U) Containing Rice Husk and an Impact Modifier
Authors: Ahmad Mazatusziha , Rahmat Abdul Razak , Hassan Azman
Published: September 2018

The objective of this study was to investigate the effects of rice husk and acrylic impact modifiers on the mechanical properties of unplasticised poly(vinyl chloride) (PVC-U) composites. The composites were prepared using a two-roll mill at temperature 165 °C before being hot pressed at 185 °C. The incorporation of rice husk (RH) fillers from 10 to 40 per hundred resin (phr) has increased the flexural and tensile modulus of the unmodified and modified (8 phr impact modifier) PVC-U composite. The flexural strength for both unmodified and modified PVC-U composite was observed to increase until RH loading of 20 phr. However, the tensile and impact strength of PVC-U composite decreased with RH loading. The scanning electron microscopy (SEM) showed that the rice husk fillers agglomerated and unevenly distributed throughout the matrix. The result showed that the impact strength of the filled PVC-U composites (20 phr filler) increased but the tensile and flexural properties decreased with increasing impact modifier content. The formulation containing 8 phr of acrylic impact modifier and 20 phr of RH loading showed the best balance of stiffness and toughness properties.
Near-Infrared Spectroscopy and Principal Components Regression for the Quality Analysis of Glass/Epoxy Prepreg
Authors: Li Wei , Gao Wei Jia , Chen Ping , Sun Bao Lei
Published: September 2018

A near-infrared (NIR) spectroscopic technique associated with a principal components regression (PCR) algorithm has been applied for rapid and nondestructive quality determination of glass/epoxy prepreg. Abundant information of prepreg related with the resin and volatile was observed in the spectra. The raw spectra and first derivative spectra over different spectral ranges were analyzed to obtain the optimum models. The models had correlation coefficients (R) of 0.950 for the volatile content and 0.981 for the resin content. The root mean square errors of prediction (RMSEP) for the volatile content and the resin content were 0.316% and 0.666%, respectively. The NIR spectroscopy method can be used to determine the resin content and the volatile content simultaneously, and the prepreg could be analyzed once within 30 s without sample destruction.
Modulating Chromium Containing Leather Wastes into Improved Composite Sheets Using Polydimethylsiloxane
Authors: Ashokkumar M. , Thanikaivelan P. , Chandrasekaran B.
Published: September 2018

Huge quantities of chrome-tanned leather wastes are produced every year from leather, footwear and clothing related industries. Many attempts have been made to reuse them in the form of boards, sheets, composites, etc. However, most of those methods have deficiencies such as low flexibility, cost effectiveness, non-eco-friendly, stringent process control and unacceptable properties. Our current work relies on an alternate method of reusing these wastes to form composite sheets with desirable characteristics. The waste chrome shavings were partially hydrolyzed and made into composite sheets using an eco-friendly polydimethylsiloxane (PDMS) polymer. The sheets were characterized for their mechanical, thermal and morphological properties. The tensile and thermal properties of composite sheets increase gradually upon increase in PDMS concentration up to 20 wt.% followed by an abrupt decrease when the PDMS concentration increased further to 30 and 40 wt.%. The softness of sheets has an inverse relationship with tensile stress and directly proportional to the elongation values. Fourier-transformed infrared (FTIR) analysis of composite sheets revealed the presence of dominant peaks corresponding to amide bands of collagen as well as characteristic bands of PDMS, showing the homogeneity of the developed composite sheets. Thus the developed composite sheets demonstrate potential for numerous applications in footwear, clothing and related industries.
Photopolymerization of Bis(4-methacryloylmethylphenyl)sulfide and Bis(4-methacryloylmethylphenyl)sulfone with Vinyl Monomers and Properties of the Prepared Copolymers
Authors: Rudź Wieslaw , Gawdzik Barbara
Published: September 2018

The reaction of photopolymerization of bis(4-methacryloylmethylphenyl)sulfide (BMcMPhS) and bis(4-methacryloylmethylphenyl)sulfone (BMcMPhSu) with the typical vinyl monomers: methyl methacrylate (MMA) and styrene (St) in the presence of the two photoinitiators: Irgacure 651 and Darocur 1173 are presented. The influence of percentage concentration of BMcMPhS and BMcMPhSu on the gelation times of the prepared copolymers was studied. The effect of the used photoinitiator concentrations on gelation times was also investigated. For the chosen copolymers, mechanical properties including tensile strength, elongation at break, Young modulus, Brinell's and Shore's hardness were determined.

The results showed that copolymers with MMA had shorter gelation times than those with St. Gelation times were shorter when Darocur 1173 was used as a photoinitiator. An increase of Darocur 1173 concentration caused a decrease of gelation times, whereas in the case of Irgacure 651 the opposite relation was observed.
Reinforced Rubber with Ionic Liquid Modifued Carbon Black
Authors: Lei Yanda , Guo Baochun , Liu Xiaoliang , Jia Demin
Published: September 2018

The ionic liquid, 1-butyl-3-methylimidazole hexafluorophosphate (BmimPF6), was utilized to modify carbon black (CB) via microwave (MW) irradiation. The conditions for the preparation of the modified CB (m-CB) were optimized. The reinforceability of the m-CB in styrene-butadiene rubber (SBR), butadiene rubber (BR) and nitrile rubber (NBR) composites were evaluated. The curing behaviour, morphology and tensile properties of the rubber/m-CB composites were studied and compared with those of composites filled with unmodified CB. Rubber/m-CB compounds showed a significant increase in the curing rate for a generated zinc complex with the alkylimidazoles. Compared with CB, m-CB exhibited a significantly improved reinforceability of the rubbers at lower filler loading, although the mechanical properties were changed slightly at higher filler loading. A possible mechanism was proposed, based on the molecular slippage theory in which the interfacial bonding, the filler loading and the chain flexibility of the rubber molecules were all considered.
Rheology, Morphology and Mechanical Property Relationship of Non-Halogen Flame Retarded Glass Fibre Reinforced Polyamide 66
Authors: Li Liping , Li Bin
Published: September 2018

In this study, the rheological behaviour of polyamide 66 (PA 66) composites consisting of flame retardant (FR)—MPP, glass fibre (GF) was characterized with a capillary rheometer at different shear rates. The effect of the shear rate on the viscosity and flow curve was discussed in terms of the power law index for non-Newtonian flow. The effect of the loading level of flame retardant on the rheological properties was studied. The results showed that MPPmodified the interfacial interaction between PA 66 and glass fibre. The PA 66/GF/MPP composite behaviour as shear thinning flow under the experimental conditions was investigated, and the investigation of activation energy showed that the proper processing temperature was 275 °C for PA 66/GF/MPP The morphology of the samples observed by scanning electron microscopy was consistent with the predictions from rheological results. The influence of rheology and morphology on the mechanical properties was also examined. It was found that mechanical strength of the composites was improved within a certain range of contents.
Mg(OH)2/polystyrene Hybrid Nanocomposite Particles Prepared by Emulsion Polymerization
Authors: Lim Kwon Taek , Parka Sung Yeol , Jeong Yeon Tae , Gal Yeong Soon , Park Chan , Kim Hyun Gyu
Published: September 2018

Core-shell type Mg(OH)2/polystyrene nanocomposite particles were prepared by the emulsion polymerization of styrene in the presence of surface-functionalized Mg(OH)2 particles. Platelet-like, 80 nm Mg(OH)2 particles were previously functionalized with 3-(trimethoxysilyl)propyl methacrylate and used for the polymerization to produce stable hybrid composite latexes. Polyencapsulation of the Mg(OH)2 particles in polystyrene matrix took place when the reaction was conducted with 10 to 30% w/w of Mg(OH)2 with respect to the monomer. With 40% loading of Mg(OH)2, an unstable latex having aggregated particles was produced. Transmission electron microscopic images revealed the hybrid composites to be multi-core/shell type encapsulated particles, while thermogravimetric analysis showed that a difference in the decomposition onset temperature of polystyrene was not apparent in the range of 0 to 40% content of nano-Mg(OH)2.
Biocompatibility In-vivo of Poly-L-lactide and Bioactive Glass Composite Substitute for Internal Fracture Fixation
Authors: Zhou Zhihua , Yi Qingfeng , Gao Yongyi , Liu Lihua , Liu Qingquan , Zhao Yanmin , Zeng Wennan , Zhou Jianan , Yang Zhongmin
Published: September 2018

Poly-L-lactide (PLLA) has been applied to bone replacement materials due to its good biocompatibility and biodegradability However, its lack of bioactivity and the release of acidic degradation products, which may lead to inflammatory responses, limit its application. Composite materials based on PLLA and bioactive glass (BG) were prepared by a moulding method and the screws were machined from the composites. The biocompatibility in vivo of PLLA/BG composite material was evaluated by haematoxylin and eosin staining, and the bone-bonding ability of PLLA/BG composite was also performed by using tetracycline staining, Von Kossa staining, Alizarin S red staining and Masson's trichromatic staining. Tissue responses evaluated for 1 to 12 weeks revealed that PLLA/BG implants were tissue tolerant and had nonbacterial inflammatory. PLGA/BG composite showed better histological compatibility than PVC implant in the in vivo study. A good ability of bone-bonding of PLLA/BG was determined by implantation into rabbit muscle and femoral condyle, and the mineralization appeared around the PLLA/BG implant materials. The results showed that PLLA/BG composites have good biocompatibility as absorbable materials for internal fracture fixation.
Mechanical Properties of Recycled Polypropylene/SBR Rubber Crumbs Blends Reinforced by Birch Wood Flour
Authors: Kakroodi Adel Ramezani , Leduc Simon , González-Núñez Rubén , Rodrigue Denis
Published: September 2018

In this work, recycled polypropylene (PP) and regenerated styrene butadiene rubber (SBR) from used tyres rubber crumbs were combined to produce polymeric blends. The compounds were prepared via twin-screw extrusion to measure their mechanical behaviour for different SBR compositions (0 to 40%). Also, the addition of birch flour (0 to 40%) and coupling agent (0 to 5 phr) content were studied. The results showed that tensile strength and modulus of the blends were substantially improved after incorporation of wood flour. The torsion modulus also increased with birch content. However, the tensile strain at break of PP/birch wood composites decreased with both wood and coupling agent contents, showing a decrease in ductility of the composites. Adding the elastomer phase did not improve the properties. The results showed that adding a coupling agent was found to be effective in improving the wood flour-PP interface, while less improvement was observed for the rubber-PP surface adhesion. The tensile strength of PP/birch composites improved by more than 60%, while the torsion and tensile moduli of the composites improved by only 10% in some cases.
The Flexural, Impact and Thermal Properties of Untreated Short Sugar Palm Fibre Reinforced High Impact Polystyrene (HIPS) Composites
Authors: Bachtiar D. , Sapuan S.M. , Khalina A. , Zainudin E.S. , Dahlan K.Z.M.
Published: September 2018

This study investigated the mechanical and thermal performance of short sugar palm (Arenga pinnata) fibre-reinforced high impact polystyrene composites. Fibre sizes of 30-50 mesh and five different fibre loadings from 10 to 50% by weight have been used. The melt mixing method and hot compression moulding were used as the fabrication techniques for the composites. The flexural behaviour, impact testing, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and the moisture absorption of short SPF-HIPS composites reinforced with varying fibre loadings were studied. The results showed that increasing the loading of short SPF in the HIPS matrix improved the flexural moduli of the composites. Lower impact strength resulted when the fibre loading was increased, and the moisture content increased significantly. The DMA test results showed increases in the storage modulus and thermal stability for the SPF-HIPS composites. Finally, the TGA test showed degradation behaviour of the composites when they were exposed to a high temperature environment. With some advantage embedding these fibres can be an alternative choice of natural fibre for reinforcing thermoplastics.
Determination of Optimum Process Parameters for Cutting Hole in a Randomly-oriented Glass Fiber Reinforced Epoxy Composite by Milling Process: Maximization of Surface Quality and Cut-hole Strength
Authors: Hussain G. , Al-Ghamdi K.A , Bijanrostami K. , Alehashemi A.J.
Published: September 2018

The epoxy based randomly-oriented glass fiber reinforced polymer (GFRP) composites are used to construct structures intended to support multi-directional loading. Due to random orientation of the fibers, cutting of high quality hole is a difficult task in such composites. In the present study, a composite with 60% glass and 40% epoxy (by volume fraction) was fabricated by hand lay-up. To begin with, the performance of two machining processes, namely twist-drilling and end-milling, was compared to cut hole in the composite. It was found that the milling performed better than the drilling process. Later, a design of experiments following the response surface methodology was conducted to determine the effect of milling parameters (i.e., feed rate and speed) on the surface quality and cut-hole strength of composite. The results showed that the parameter-response relationship was not straight rather the parametric effects were interactive and complex. Further, the relative value of speed and feed rate was observed to have controlling influence on the process performance. To predict the process performance for a given set of conditions, empirical models were proposed. Finally, the optimal parameters minimizing the surface roughness and maximizing the tensile strength, employing desirability function approach, was carried out so as to provide guidelines to the users.
A Novel Approach for Fabricating Poly-L-lactide Materials by One-step Bulk Polymerization
Authors: Peng Zhiyuan , Li Zhiping , Zhang Fan , Peng Xiaochun
Published: September 2018

Poly-L-lactide (PLLA) is one of the most significant members of a group of bioabsorbable polymers. A new approach for fabricating PLLA material was investigated by one-step bulk polymerization. The focus of this paper was on the effect of reaction temperature and reaction time on the weight-average molar mass, the polydispersity index (PDI), and the flexural strength and modulus. Gel permeation chromatography (GPC), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and mechanical properties measurements were used to characterize the products. It was found that the optimal reaction conditions were at 140 °C for 24 h, under which the highest [Formula: see text] (5.02 × 105 Da) and the lowest PDI (1.16) were reached. In addition this material had the highest flexural strength and modulus, 74.58 ± 2.35 MPa and 1.62 ± 0.14 GPa, respectively.
A Study of Bubble Electrospinning of Ethylcellulose Ultrafine Fibres
Authors: Vadodaria Ketankumar , Stylios George
Published: September 2018

Bubble electrospinning (BE) is a recently-invented simple needleless concept to produce nanofibres. The bubble electrospinning method is not yet well established and there is a need to study the effects of different parameters on the fibre morphology. In the present work, ethylcellulose (EC) was successfully electrospun from 15% EC solution in toluene:ethanol (60:40) by bubble electrospinning. The effects of different parameters such as solution surface to collector distance and applied voltage on the morphology of bubble electrospun EC nanofibres were studied and are discussed below. Bubble electrospun EC fibres showed an increase in diameter as the distance between solution surface and collector increased. However, when the applied voltage was increased, the EC fibre diameter was initially reduced but then increased. The results are discussed in detail in the paper. FTIR analysis of EC powder, solution and fibres were also studied.
Evaluation of Glass/Carbon Reinforced Polymer Composites
Authors: Vinay H.B. , Govindaraju H.K. , Banakar Prashanth
Published: September 2018

Polymer composites are used in various applications because of its universal properties. In the present investigation the vinyl ester matrix composites were developed with glass fiber and carbon fiber as reinforcements. The composites were manufactured by using hand layup process and the tests were conducted as per ASTM testing standards. The inter laminar shear strength and impact strength of carbon reinforced composites have improved when compared with glass fiber reinforced composites. Whereas glass fiber reinforced composites have shown better shore-D hardness.
Incremental Forming of Polymer-Numerical and Experimental Investigation
Authors: Sridhar R. , Rajenthirakumar D.
Published: September 2018

In current competitive market every day a new design and manufacturing concept is evolved in polymer processing technology. The industries to cater the need of customers, apart from conventional polymer part manufacturing processes they are in need to develop new manufacturing techniques. This necessitates the need for new flexible polymer processing method that reduces design and manufacturing lead time. Research is on to develop new innovative process strategies and methods in the area of polymer processing. Such one technology is incremental forming (IF) of polymers. In this incremental polymer sheet forming process there is no need to develop dedicated dies and moulds. As a result high investment on moulds and dies was totally eliminated. It is a very much flexible part forming process and is enabled with the help of Computer Numerical Control (CNC) technology. In this paper, numerical and experimental investigations are carried out for the applicability of Incremental forming in polymer part manufacturing. A Finite Element (FE) model is developed for the 3-D numerical simulation of incremental forming process of polymers using commercial software HYPERFORM. The developed model can predict the thickness distribution and percentage thinning of the blank. The FEA results and experimental results are compared for validation with the part design parameters (geometrical and physical parameters). Furthermore, this numerical simulation predicts the failure of polymers in IF process and it is verified with experimental results. By this numerical simulation, failure prediction can be done without expensive shop trials.
Optimization of Process Parameters in Micro-Drilling of Carbon Fiber Reinforced Polymer (Cfrp) Using Taguchi and Grey Relational Analysis
Authors: Shunmugesh K. , Panneerselvam K.
Published: September 2018

Carbon fiber reinforced polymer (CFRP) are said to be an excellent replacement for conventional materials with high strength and modulus and are widely used in aircraft, automobiles, infrastructures, 3D printing etc. In this micro-drilling experimental study, through holes are drilled on a CFRP laminates of 2 mm thick using conventional HSS drill bit of three different diameters (0.7, 0.8 and 0.9 mm). The Taguchi's L27(313) orthogonal array experimental design with smaller-the-better characteristics are selected as the input to the Grey relational analysis (GRA) to simultaneously minimize the delamination factor, circularity and cylindricity. The effect and contribution of the process parameters namely, spindle speed and feed rate are determined using analysis of variance (ANOVA). The correlation of process parameter and the responses are established using response surface methodology (RSM). The analysis of the results reveals that feed rate and spindle speed combination significantly affects the multiple response characteristics.
Multi Objective Optimization Using Taguchi Grey Relational Analysis (Gra) for Cnc Turning of Poly-Ether-Ether-Ketone (Peek) Polymer
Authors: Jogi Bhagwan F , Tarekar Monish , Dhajekar Rinul M , Pawade Raju
Published: September 2018

The paper attempts to implement the multi objective optimization methodology for poly-ether-ether-ketone (PEEK) polymer by using CNC turning machine. For the same, Taguchi based L18 experiments were carried out on CNC turning lathe using TiC and TiN coated carbide inserts. Further, the process performance is measured in terms of cutting forces and surface roughness. The optimized machining parameters were determined using Grey Relational Analysis (GRA). The analysis of results shows that cutting speed: 377 m/min, feed rate: 0.05 mm/rev, depth of cut: 2 mm and TiC insert exhibits better results.
Thermal Crosslinking of Maltodextrin and Citric Acid. Methodology to Control the Polycondensation Reaction under Processing Conditions
Authors: Castro-Cabado M. , Parra-Ruiz Francisco J. , Casado A.L. , Román J. San
Published: September 2018

This paper presents an affordable methodology for the analysis of the crosslinking, by polycondensation reaction, between maltodextrin and citric acid under thermal processing. This methodology is based on three complementary analytical techniques: Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and rheometry. FTIR has been found to be a powerful technique for the characterization of both the esterification reaction and other non-covalent interactions between maltodextrin and citric acid. TGA has been mainly applied to quantify the progress of the polycondensation reaction. Rheometry has been extensively used to understand the crosslink formation resulting from the polycondensation process between maltodextrin and citric acid, allowing the determination of the gel time. Furthermore, these techniques have revealed added value when used as complementary techniques. For instance, the FTIR results supported the conclusions from the study of polycondensation reaction progress by TGA. Similarly, the TGA results about the polycondensation reaction temperature are consistent with the rheology study. Overall, the insightfulness and accuracy of the methodology presented in this paper make it very useful as a tool to optimize industrial processing of materials which apply binding systems based on maltodextrin and citric acid.
Microcrystalline Cellulose from Oil Palm Empty Fruit Bunches as Filler in Polylactic Acid
Authors: Haafiz M.K. Mohamad , Hassan Azman , Arjmandi Reza , Zakaria Zainoha , Marliana M.M. , Syakir Muhammad I. , Fazita M.R. Nurul
Published: September 2018

Acid hydrolysis method was used to isolate microcrystalline cellulose (MCC) from oil palm empty fruit bunches (OPEFB) total chlorine free bleached pulp. The derived MCC was incorporated into polylactic acid (PLA) using solution casting technique in order to produce PLA/MCC composites. The chemical structure of the cellulose fragments remains unaltered as demonstrated by Fourier transform infrared spectroscopy despite acid hydrolysis. X-ray diffraction showed that the MCC has a cellulose I polymorph with 87% crystallinity index. The addition of MCC into PLA enhanced not only the thermal stability but also the Young's modulus of the PLA/MCC composites by approximately 30% at 5 phr MCC contents compared to pure PLA. However a decrease in tensile strength and elongation at break of the PLA/MCC composites were observed due to the poor dispersion of MCC in the PLA matrix
Exploring the Potentials of Nanocellulose Whiskers Derived from Oil Palm Empty Fruit Bunch on the Development of Polylactid Acid Based Green Nanocomposites
Authors: Haafiz M.K. Mohamad , Hassan Azman , Arjmandi Reza , Marliana M.M. , Fazita M.R. Nurul
Published: September 2018

In this study, nanocellulose whiskers (NCW) from oil palm empty fruit bunches (OPEFB) were used as reinforcement phase in polylactid acid (PLA). Two techniques were employed to isolate the NCW from OPEFB microcrystalline cellulose (OPEFB-MCC); chemical swelling with DMAc containing 0.5% LiCl to generate the NCW and acid hydrolysis with 64% H2SO4 to generate the NCW-S. The atomic force microscopy showed that the isolated NCW and NCW-S are in nanoscale dimension and displayed an individual rod-like structure. The fillers were then incorporated in PLA matrix at different loadings (1, 3, and 5 parts per hundred resin (phr)) to produce P-NCW and P-NCW-S nanocomposites via solution casting technique. The mechanical properties of the developed nanocomposites were investigated by means of tensile test. The results showed that the tensile strength of nanocomposites increased by 84% and 64% for the NCW and NCW-S reinforced PLA nanocomposites, respectively. The Young's modulus of nanocomposites increased linearly with the fillers loading. Expectedly, the percent elongation at break was impacted negatively as it decreased with fillers loading. The thermogravimetric analysis showed that the decomposition temperatures (T10, T50 and Tmax) of P-NCW were higher than neat PLA. In the case of P-NCW-S however, the thermal stability decreased with the additional of NCW-S.
Mechanical, Thermal and Instrumented Impact Properties of Bamboo Fabric-Reinforced Polypropylene Composites
Authors: Zuhudi N.Z. Mahmud , Jayaraman K. , Lin R.J.T.
Published: September 2018

Many automotive companies are experimenting with natural fibres as a substitute for glass fibres in polymer composites, especially polypropylene (PP) based composites. PP composites reinforced by plain woven bamboo fabric have recently been widely investigated. Bamboo in woven fabric form embedded in the polymer results in easier material handling during production and reduction in the manufacturing cost of the composites. In the current study, the performance of twill-weave bamboo fabric-reinforced PP composites, which were fabricated using a compression moulding method, was evaluated. The mechanical, thermal and impact performances of the bamboo fabric-reinforced PP (BPP) composites were evaluated in comparison to those of PP, at various bamboo contents and stacking sequences. The incorporation of bamboo fabric resulted in the improvement of tensile strength, tensile modulus, flexural strength, flexural modulus and Charpy impact strength of PP by 238%, 110%, 180%, 170% and 160%, respectively. The integration of bamboo fabric slightly increased the melting temperature and the degree of crystallinity of the composites. A 40% decrease in the heat of fusion of the composites was observed compared to that of PP. Impact tests were also conducted using an instrumented drop weight impact test system. The perforation impact energy, peak load and energy absorbed of the composites increased when the bamboo content was increased. The perforation impact energy was at 55 J for the BPP50% composite, compared to that of neat PP at 20 J. The crack damage in the composites was also reduced with the presence of fabric reinforcement. These results indicate that bamboo fabric is truly a new contender for developing excellent and economical light-weight composites as interior components in automobiles.
Reused Carbon Fibre as Reinforcing Filler in Palm-Based Polyurethane Composites
Authors: Zaini Mariana Mohd , Norzali Nor Rabbiatul Adawiyah , Badri Khairiah Haji
Published: September 2018

The loading effect of recycled carbon fibre at 5, 10, 15 and 20 wt.% on the mechanical strength of the palm-based polyurethane (PU-rCF) was investigated. The recycled carbon fibre (rCF) from glycolysis of the carbon fibre-epoxy mat (CFRP) was obtained. The glycolysis was conducted at 180–190 °C under atmospheric pressure and catalysed by 1.9 wt.% NaOH in 80% aqueous medium. The rCF was analysed by FTIR spectroscopy analysis and SEM observation. Clean fibre without residual traces was obtained. The rCF was then incorporated into palm-based polyurethane to form composite panel (PU-rCF). The addition of rCF improved the mechanical strength of the composite. The impact strength increased more than 3 folds from 0.6 kJ/m2 to 3.8 kJ/m2 while the flexural strength increased from 43 MPa to 61 MPa. The shore D hardness index was at the highest (72) with maximum rCF loading of 20 wt.%. As expected, the FTIR spectrum of the PU-rCF indicated the absence of chemical interaction between PU and the rCF. The strong physical interaction between the rCF fibre strands has decreased the brittleness of the PU and increased the mechanical strength of the composites.
Hong Kong Poison Information Centre: Annual report 2017
Authors: Lau Kai Kee , Chow Tin Yat Anthony , Chan Chi Keung , Chan Yiu Cheung , Ng Chun Ho Vember , Ng Sze Hong , Tse Man Li
Published: September 2018

Objectives:

To report and analyse the poisoning data of Hong Kong Poison Information Centre in 2017.

Methods:

In 2017, all poisoning cases received by Hong Kong Poison Information Centre were retrieved from its database (Poison Information and Clinical Management System) for analysis.

Results:

A total of 3956 poisoned cases were analysed. There were 1789 male patients (45.2%), 2159 female patients (54.6%) and 8 sex‐unspecified patients (0.2%). The majority of cases (59.9%) were between 20 and 59 years old. The common causes of poisoning were suspected self‐harm/suicidal attempt (36.2%), unintentional exposure (18.6%) and abusive substance use (13.7%). Excluding the common co‐ingestant ethanol, the five commonest types of poison were benzodiazepines, paracetamol, zopiclone, Chinese herbal medicine and household products. Most patients were managed with supportive measures, while 17.4% and 13.2% of consultation cases were treated by decontamination and antidotes, respectively. The majority of the cases had uneventful recovery; 1.1% resulted in death and 4.3% had major outcomes. A total of 13 interesting cases and 1 poisoning outbreak were discussed.

Conclusion:

This 12th annual report provided the updated epidemiological information on poisoning pattern in Hong Kong and highlighted important changes in comparison with our previous reports.
The Social Determinants of Nursing Retention in a Pediatric Hematology/Oncology Unit
Authors: Mahon Paula R.
Published: September 2018

Pediatric hematology/oncology units (PHOUs) are highly paced, stressful environments and can be difficult areas to work. Thus, these units can present issues when it comes to both recruiting and retaining health care professionals (HCPs). There is scant research addressing how the environment of a PHOU contribute to a HCP’s desire to stay or leave this environment. To conduct this project, a critical ethnographic approach was used. The researcher conducted semistructured interviews ( n = 29), which included nurses ( n = 21), physicians ( n = 4), and allied health care staff ( n = 4). This sample represented approximately one third of staff in each category. Participants identified that their ability to develop long-term relationships with children and families as a significant source of satisfaction. Belonging to the oncology team was seen as extraordinarily important to all the participants. The majority of the participants also felt that working in this ever-evolving dynamic medical field afforded them with ongoing learning opportunities. The main frustration described by participants pertained to administrative involvement in the everyday workings of the PHOU, potentially leading to attrition. It is important to note that there was also diversity among and between the categories of HCPs when describing the work environment and the issues that most influence them. While similarities among participants were found between satisfaction and dissatisfaction, significant differences between them led us to believe it would be unreasonable to attempt to compare the three groups here. Thus, in this article the author focused primarily on nursing while noting related observations from physicians and allied health professions.
The first-level digital divide shifts from inequalities in physical access to inequalities in material access
Authors: van Deursen Alexander JAM , van Dijk Jan AGM
Published: September 2018

For a long time, a common opinion among policy-makers was that the digital divide problem would be solved when a country’s Internet connection rate reaches saturation. However, scholars of the second-level digital divide have concluded that the divides in Internet skills and type of use continue to expand even after physical access is universal. This study—based on an online survey among a representative sample of the Dutch population—indicates that the first-level digital divide remains a problem in one of the richest and most technologically advanced countries in the world. By extending basic physical access combined with material access, the study finds that a diversity in access to devices and peripherals, device-related opportunities, and the ongoing expenses required to maintain the hardware, software, and subscriptions affect existing inequalities related to Internet skills, uses, and outcomes.
Mapping the emotional labor and work of visual journalism
Authors: Thomson TJ
Published: September 2018

The study of emotion in journalism has largely been ignored and, when studied, is relegated almost exclusively to media texts. As such, this research aims to rectify this imbalance by focusing on the human side of journalism practice and the emotional labor and work experienced by documentary visual journalists. It does so through an in-depth, interview-based approach with 23 journalists in eight countries and identifies the sources of emotional labor and work experienced by those in the profession and how visual journalists manage the effects of the emotional labor and work they experience. The findings suggest that emotional labor and work pervade the production, editing, and post-production phases of journalistic work but not equally for all types of visual journalists. Female journalists, in particular, reported unique emotional investment and display practices, while a subset of male journalists reported unique emotional management ones. In addition, almost across the board, the visual journalists in this sample reported relying on more informal rather than formal strategies to manage the effects of their work-related emotions.
PVC / Nitrile Rubber Blends
Authors: Thomas N.L. , Harvey R.J.
Published: September 2018

Blending of nitrile rubber with plasticised PVC produces vinyl-based thermoplastic elastomers. These materials offer a versatile range of properties and are used in numerous applications; such as glazing gaskets, footwear, cable jacketing, hose, tubing and coated fabrics. In this paper it is discussed how the properties vary as a function of the PVC / plasticiser / nitrile rubber composition. It is shown how, with appropriate experimental design, it is possible to model the results and produce contour plots to map the properties as a function of the formulation
Manufacture of Sheets Using Post-Consumer Unsaturated Polyester Resin/Glass Fibre Composites
Authors: Pedroso A. G. , Rosa D. S. , Atvars T. D. Z.
Published: September 2018

The storage of post-consumer unsaturated polyester/glass fibre composites impacts negatively on the environment due to its persistence (long lifetime of both the glass fibre and the resin) as well as the high volume/weight ratio of the residues. In this work we introduce a new approach for the recycling process of artefacts made of these polyester/glass fibre composites that involves the dispersion of the ground, not powdered, composite in raw polyester resin. Room temperature resin curing was employed. Flexural and impact tests were performed to optimize the processing conditions and the manufacturing process. Significant improvement in texture, flexural strength and impact resistance of sheets were achieved by pressing and heating the sheets at 40∞C and 50∞C during curing. The artefacts utilized in our work were post-consumer public telephone weather protector caps, which, in Brazil, are manufactured with a composite of unsaturated polyester/glass fibre. Although we used this specific artefact, the methodology can be extended to different types of post-consumer materials or industrial scraps.
Effect of Urethane Based Bonding Agent on the Cure Characteristics and Mechanical Properties of Styrene Butadiene Rubber – Whole Tyre Reclaim - Short Nylon Fiber Composite
Authors: Sreeja T.D. , Kutty S.K.N.
Published: September 2018

The cure characteristics and mechanical properties of short nylon fiber – styrene butadiene rubber/whole tyre reclaim (SBR/WTR) composites with and without an interfacial bonding agent based on 4,4 diphenyl methane diisocyanate and polyethylene glycol (MDI/PEG) have been studied. An 80:40 blend of SBR/WTR reinforced with 20 phr of short nylon fiber has been selected and the MDI/PEG ratio has been changed from 0.67:1 to 2:1. The minimum and maximum torques increased with isocyanate concentration. The scorch time and cure time showed an initial reduction. The cure rate showed an initial improvement. Tensile strength, tear strength and abrasion resistance increased with MDI/PEG ratio, these values were higher in longitudinal direction. Resilience and compression set increased with isocyanate concentration.
Thermogravimetric Studies of the Decomposition Kinetics of Four Different Hevea Rubber Clones using Ozawa's Approach
Authors: de Medeiros Eliton S. , Moreno Rogέrio M. B. , Ferreira Fábio C. , Alves Neri , Job Aldo E. , Gonçalves Paulo S. , Mattoso Luiz H. C.
Published: September 2018

Thermal degradation behavior of rubber from four rubber clones (RRIM 600, PB 235, GT1 and IAN 873) of the Hevea brasiliensis species was studied by thermogravimetry (TG) using Ozawa's approach to assess the kinetic parameters of the decomposition process. These parameters indicated that the thermal behavior of natural rubber depends on the type of rubber clones studied. The order of reaction was found to be dependent on the degree of conversion indicating that both the early and the latter stages of rubber degradation follow zero or pseudo-zero order kinetics whereas the intermediate stages follow a first order kinetics and the activation energy was found to be dependent on the degree of conversion and the type of clone used ragging from 148 to 236 kJ/mol. Rubber from clones IAN 873, GT1 and RRIM 600 presented the best overall thermal stability whereas the clone PB 235 presented the lowest thermal stability, therefore in agreement with the plasticity retention index (PRI) behavior.
Studies on a Novel Accelerator System in the Vulcanisation of Polychloroprene Rubber
Authors: Susamma A.P , Kuriakose A.P
Published: September 2018

Polychloroprene (CR) is a polar rubber and its compounding, curing etc. are somewhat different from other hydrocarbon rubbers. Thiourea derivatives are popular in neoprene compounding. For example ethylene thiourea (NA22) is a common ingredient of compounding of this rubber. Metal oxides are also an important part of the curing system in CR. Considering the carbon backbone structure with double bonds sulphur crosslinking is also sometimes followed. It is to be emphasised that the conventional accelerators used in CR vulcanisation especially NA22 is a toxic chemical and is reported to be carcinogenic. In our studies we tried sulphur vulcanisation of Neoprene-W along with MgO and amidinophenyl thiourea (APT) which is a non-toxic chemical used in the pharmaceutical industry. TMTD-NA22 combinations are used as controls. Investigations were carried out to find out the effect of this amidinothiourea derivative on filled CR systems also. Carbon black and precipitated silica were used as fillers. From our investigations it is found that experimental mixes containing TMTD-APT are effective in the vulcanisation of polychloroprene rubber. A nucleophilic reaction mechanism for the above vulcanisation reactions can also be envisaged. The cure characteristics and tensile and other physical properties evaluated are found to be better/comparable to the control systems in both gum and filled formulations studied. The percentage retention of tensile properties of the vulcanisates containing APT is also found to be satisfactory. Non-toxic nature of this amidinothiourea derivative will be an added advantage in this context.
Use of Ground Tyre Rubber (GTR) in Thermoplastic Polyolefin Elastomer Compositions
Authors: Lievana E. , Karger-Kocsis J.
Published: September 2018

A novel method was proposed to produce thermoplastic elastomers containing ground tyre rubber (GTR). The new proprietary technology is based on the fact that bitumen and related materials may contribute to the devulcanisation of GTR and act at the same time as plasticiser and compatibiliser in the blends. Blends containing polyolefins, olefinic type rubbers and GTR treated with bitumen showed outstanding mechanical properties and met the requirements with thermoplastic rubbers. It was established that the conditions of the GTR treatment by bitumen strongly affect the performance of the compounds. Scanning electron microscopy (SEM) results revealed a good adhesion between the GTR particles and the surrounding matrix. The apparent particle size of GTR was reduced owing to the treatise with bitumen, which is an indirect hint for GTR devulcanisation.
Polymer Mechanical Recycling: Downcycling or Upcycling?
Authors: La Mantia Francesco Paolo
Published: September 2018

Recycled plastics are considered as materials with physical, mechanical and aesthetic properties worse than the virgin ones. In fact, this is true because degradation during lifetime and during the recycling operations changes the structure and the morphology of the polymers and then the final properties of the secondary material. Several “strategies” are under investigation, and in some cases also applied, in order to avoid further degradation during recycling and, if possible, to repair the macromolecules broken during lifetime and then to restore or to improve the initial properties.

In this paper the more important techniques, already used in industry or under investigation, according to this philosophy are shortly reviewed.