bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Thermoplastic Polyurethane Composites Based on Reclaimed Polyurethane Foam and Ground Fluoroelastomer: Effect of Pretreatment of Fluoroelastomer through Solid-State Mechanochemical Milling
Authors: Li Hua , Zhang Xinxing , Lu Canhui , Liang Mei
Published: September 2018

Thermoplastic polyurethane composites were made from ground fluoroelastomer (FKM) and reclaimed polyurethane (PU) foam which derived from shoe making industry through melt-mixing. Pan-mill type mechanochemical reactor made in our lab was applied to realise the devulcanisation and ultrafine pulverisation of FKM, thereby to enhance mechanical properties of the composites. Fluorescence microscopy studies indicated that the dispersion of devulcanised FKM in PU matrix was much better than ground FKM. Glass transition temperature of devulcanised FKM filled-PU composites was higher than that of pristine PU, as confirmed by differential scanning calorimetry and dynamic mechanical analysis. The mechanochemical devulcanisation of FKM significantly enhanced the mechanical properties of FKM/PU composites. When the content of FKM was 20%, the tensile strength of the composites was enhanced from 13.2 MPa to 23.2 MPa through devulcanisation, by about 80.2%; and the elongation at break was increased from 380.2% to 500.2%, by about 30.2%. Furthermore, the onset degradation temperature increased from 252.8°C to 273.3°C with the addition of 100 phr devulcanised FKM powder.
Kinetics of Peroxide Vulcanization of Natural Rubber
Authors: Rajan Rejitha , Varghese Siby , George K.E.
Published: September 2018

This study was undertaken to optimize the vulcanization conditions and explore the effect of residual peroxide in the peroxide vulcanization of natural rubber. The study was followed through the kinetics of the vulcanization reaction at various temperatures viz. 150,155,160 and 165°C. Dicumyl peroxide (DCP) was used as the crosslinking agent. The Monsanto Rheometer was used to investigate the different crosslinking stages and vulcanization kinetics. The thermal decomposition of peroxide followed a first order free radical decomposition reaction. Half-lives at various temperatures were determined. The percentage of residual peroxide was calculated from the cure kinetic data. The effect of residual peroxide on mechanical properties was studied at various peroxide levels and also by extending the cure time (from t90 to t95 and then to t100). Mechanical properties such as tensile strength, elongation at break, modulus and compression set (70 and 100°C) were measured. Excess peroxide was found to cause a high compression set at elevated temperature and the cure time was selected to achieve minimum residual peroxide in the product. Results indicate that peroxide concentration is the dominant factor controlling the crosslink density and hence the properties of the vulcanizates.
Degradation Behaviour of Natural Rubber Layered Silicate Nanocomposites
Authors: Mathew Shera , Varghese Siby , Joseph Rani
Published: September 2018

The degradation behaviour of natural rubber latex nanocomposites employing various degrading agents viz. thermal, gamma and UV radiations, chlorination, sterilization, ozone and solvents, was studied in detail. It was found that the layered silicate nanocomposite performed well in the presence of most of the degrading agents and such materials are suitable for processes such as chlorination, sterilization etc. It was observed that the degrading action was arrested either due to the hindrance exerted by the clay layers against crack propagation or due to the barrier effect against the degrading agents. A better interaction of nanosilicates was found with a polymer matrix due to their higher surface area, making the matrix stiffer and the diffusion of heat and gases through the bulk more difficult hence, retarding the degradation of the composite. These points were illustrated using XRD, TEM, SEM and TGA studies. Kraus plot showed a strong filler-rubber interface in rubber nanocomposites. Schematic representation of the degradation of the nanocomposite demonstrated the effect of nanofillers in chain scission or crosslinking, which may occur during degradation.
Morphology, Foaming Rheology and Physical Properties of Ethylene-Propylene Diene Rubber/Ground Tyre Rubber (GTR) Composite Foams: Effect of Mechanochemical Devulcanisation of GTR
Authors: Zhang Xinxing , Tian Dong , Zhang Wei , Zhu Jian , Lu Canhui
Published: September 2018

In this study, an attempt was made to enhance the foamability and physical properties of ethylene-propylene diene (EPDM) rubber/ground tyre rubber (GTR) composite foams, thereby providing a potential new route to recycle discarded tyres. Pan-mill type mechanochemical reactor made in our lab was applied to realise the partial devulcanisation and ultrafine pulverisation of GTR. Fluorescence microscopy and scanning electron microscopy (SEM) studies indicated that the dispersion and interfacial adhesion between devulcanised GTR and EPDM matrix was much better than that of the untreated GTR and EPDM. The enhanced foamability through devulcanisation of GTR was confirmed by foaming rheological analysis. The physical properties of the composite foams were significantly improved through the devulcanisation of GTR. For the EPDM/GTR (100/30) composite foams, the rebound resistance was enhanced from 37% to 51% while the compression set was decreased from 43% to 33% via the devulcanisation of GTR. It has been proved that the mechanochemically devulcanised GTR can be used as a low cost but effective functional additive for enhancing the rebound resistance properties of EPDM foams.
Studies on Non-regulated Safe Binary Accelerator System for Efficient Vulcanisation of Natural Rubber
Authors: Abhitha K. , Kurian Philip , Kurian Thomas , Jayabalan L.
Published: September 2018

Nitrosamines (NA) reported to be found in rubber products vulcanized using conventional accelerators such as tetramethylthiuramdisulphide (TMTD) are carcinogenic. Tetra benzyl thiuramdisulphide (TBzTD) has been used in an efficient vulcanisation (EV) system to prepare rubber vulcanisates having properties comparable to the vulcanisate prepared using TMTD. TBzTD is reported to be non regulated and safe. The compound containing TBzTD shows better scorch safety. The novel safe vulcanisate shows comparable mechanical properties, crosslink density and improved aging resistance.
Probabilistic and Statistical Modelling of Long-Term Behaviour of Composites Systems
Authors: Ulianov C. , Lupescu O. , Palacin R.
Published: September 2018

The paper review and analyses some of the most relevant literature approaches on the empirical, probabilistic and statistical modelling of long-term behaviour of composite structures and systems and try to suggest some future directions that should be assumed in conceiving of useful models. A critical analysis of deterministic approaches and a comparison between the new probabilistic and statistical solutions is presented. The authors’ point of view on the recommended approaches for different types of composites structures is detailed and exemplified.
Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Concrete Pavement Applications
Authors: Dong-Hyun  , Kim  , Chan-Gi  , Park
Published: September 2018

The objective of this study was to improve the performance of a pavement structure by applying precast concrete to enable rapid repair of the pavement. Latex-modified fibre-reinforced concrete (LMFRC) was used to achieve this objective. This study also determined the type of fibre reinforcement and the amount of added latex that exhibited the best performance. Three types of reinforcing fibres were evaluated: polyvinyl alcohol (PVA), polypropylene (PP), and nylon fibre. Latex was added to the LMFRCs at 0, 5, 10, and 15% of the cement weight. The LMFRC was tested for slump, compressive strength, flexural strength, chloride-ion penetration, abrasion resistance, and impact resistance. Test results showed that increasing latex content improved the flexural strength, permeability resistance, abrasion resistance, and impact resistance. When comparing the types of reinforced fibre, the hydrophilic PVA and nylon fibres showed superior resistance to microcracking and crack propagation due to their stronger bonding with the concrete matrix compared with the non-hydrophilic PP fibre. Consequently, the concrete containing the nylon fibre had the best performance, proving that nylon fibre is the most desirable reinforcing fibre for precast concrete pavement.
Integrated Methodology for Economic Incentive Materials
Authors: Chauhan Ashish , Chauhan Priyanka , Kaith Balbir
Published: September 2018

Nature has gifted mankind with precious resources on earth. A major part of the earth provides us with renewable biomass that mostly degrades with time. Graft copolymerization is a chemical technique to improve the properties of the waste biomass and to modify its properties while sustaining the inherent trait. With the advancement of science and research many efforts have been made to modify the techniques. This review explores a brief overview of this magnificent engineering, its techniques and characterization that has helped to provide with outstanding results for better scientific and industrial achievements.
Preparation and Properties of Chemical Resistant Conductive Composites with Restrained Negative Temperature Coefficient Behaviour Based on Mechanochemically Devulcanised Waste Fluoroelastomers
Authors: Wu Xiaodong , Zhang Xinxing , Zhang Wei , Tian Dong , Li Jie , Lu Canhui
Published: September 2018

The presence of negative temperature coefficient (NTC) effect is harmful to temperature auto-control and also hinders the application of self-regulating heater materials. Mechanochemically devulcanised waste fluoroelastomer (FKM) can hinder the aggregation of conducting fillers and inhibit the NTC effect. Herein, we report for the first time that the devulcanised FKM can be used as low cost but effective functional filler for making chemical resistant conductive composites with restrained NTC effect. The NTC effect was notably restrained via introducing devulcanised FKM into the carbon black-filled poly(vinylidene fluoride) composites. A platform with a volume resistivity higher than 106 Ω•cm was observed at temperature range of 167–180°C. The crystallization imperfection and limited mobility of carbon black induced by the well dispersed FKM powders are responsible for the delay of NTC effect. Furthermore, the mechanical properties of the composites were significantly improved through the mechanochemical pretreatment of FKM. Meanwhile, the devulcanised FKM-filled composites have excellent chemical resistance. The stable resistivity in a wide temperature range of the prepared low cost composites gives them attractive prospects as over current and temperature sensor materials.
Preparation and Properties of Polyvinyl Alcohol/Banana Frond Flour Biodegradable Film
Authors: Suki F.M. Mat , Ismail H. , Hamid Z.A. Abdul
Published: September 2018

A series of biodegradable films, based on polyvinyl alcohol (PVA) and banana frond flour (BFF) was prepared using a solution-casting method. BFF was added to PVA in order to improve biodegradability and reduce cost. The blended films were evaluated for their tensile properties, water absorption, water vapour transmissibility (WVT) and degradation under natural weathering. Tensile strength and elongation at the break of PVA/BFF films were lower than unfilled PVA film, but the tensile modulus was higher. Water absorption and WVT of the blended films increased upon increasing the BFF content. The presence of BFF influences degradation and causes a reduction of the tensile properties of the PVA/BFF blended films.
Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion: Effects of Vulcanizing Systems and Fillers
Authors: Patcharaphun Somjate , Sukniyom Yanichsa , Chookaew Watcharapong , Sombatsompop Narongrit
Published: September 2018

This work aimed to make use of a rate-controlled capillary rheometer for investigating the effects of vulcanizing system using various fillers on the apparent viscosity and extrudate swelling of natural rubber (NR) compounds. The results suggested that the rubber compounds exhibited a pseudoplastic non-Newtonian behavior. At any given shear rates, the viscosities of rubber compound utilizing conventional (CV) and efficient vulcanizing (EV) systems were lower than that of non-sulfur (NS) system. This was due to the occurrence of premature crosslinking at the skin layer and subsequently led to the wall slip of rubber compound during the flow in capillary die. The irregular surface and the onset of smooth surface of rubber extrudate were evidently seen, especially for CV and EV systems. This could be associated with the amount of required energy to obtain the steady state flow in the die. The results also suggested that the swelling ratio of rubber extrudate ranged from 1.2 to 2.2 and the effect of filler type was more pronounced at high shear rates above 400 s−1. In the case of silica filler (SiO2) system, the severe irregularity of rubber extrudate was observed. The lower shear rate employed to obtain the smooth surface for rubber extrudate containing 30 phr of SiO2 was possibly caused by high amount of PEG acting as an external lubricant which promoted the uniform slippage during the flow in capillary die.
Eco-Friendly Method for Recovery of Bisphenol-A from Cd Waste over Nanoclay as the Solid Support
Authors: Nikje Mir Mohammad Alavi , Askarzadeh Mohammad
Published: September 2018

Received polycarbonate wastes from used optical discs chemically recycled to Bisphenol- A by using water as the solvent, Cloisite 30B nanoclay and sodium hydroxide as the support and catalyst, respectively at convenient, green and eco-friendly conditions. The performances of the support in Bisphenol- A recovery yield were examined in comparison with the unsupported as well as nano-SiO2 and nano-TiO2 supported reactions. The optimum condition by having 90% recovery yield was found at 90 min when the reaction performed at equal waste/solvent ratio, catalyst 1% and nanoclay 2%.
Effect of N, N-M-Phenylenebismaleimide on Thermodynamics Properties of Epoxidised Natural Rubber by Using Differential Scanning Calorimeter
Authors: Alwaan I.M. , Hassan A.
Published: September 2018

The thermodynamics properties of pure epoxidised natural rubber (ENR-50) and epoxidised natural rubber/N, N-M-Phenylenebismaleimide (ENR-50/HVA-2) compound were measured by differential scanning calorimeter (DSC) at a heat rate 10 K/min and at temperatures ranging from 273.15 to 453.15 K. The equations and values of heat capacity, enthalpy, entropy, Gibbs free energy and internal energy of pure ENR-50 and ENR-50/HVA-2 were found to be functions of temperature. The equations of heat capacity, enthalpy and internal energy of pure ENR-50 and ENR-50/HVA-2 compound behaved as polynomial equations with temperature at different order, while entropy and Gibbs free energy of pure ENR-50 and ENR-50/HVA-2 compound behaved as exponential equations with temperature. The Gibbs free energy for both substances was a negative value for all temperatures ranging from 273.15 to 453.15 K.
Resistance to Thermal Degradation of Polypropylene in Presence of Nano Zinc Oxide
Authors: Esthappan Saisy K. , Joseph Rani
Published: September 2018

Polypropylene/zinc oxide composites were prepared using melt mixing method and made into sheets using compression moulding. 0–5 wt% of zinc oxide (ZnO) with different crystallite sizes were incorporated into the polypropylene (PP). Mechanical properties of the PP were increased by the addition of ZnO. Morphology of the composites showed good dispersion of ZnO in the composites. Thermal ageing was carried out on neat PP and composites for 24 hrs. Mechanical properties of the PP and composites were decreased after thermal ageing. However composites showed increased properties compared to neat PP even after thermal ageing. IR studies indicated better thermal stability of PP in presence of ZnO. PP filled with less crystallite size ZnO showed better properties compared to PP filled with high crystallite size ZnO and neat PP.
Research on Vulcanization Process Simulation of Butyl Rubber Based on a New Characterization Model of Curing Degree
Authors: Jian Wu , Benlong Su , Qiang Liu , Youshan Wang
Published: September 2018

Butyl rubber is an isobutylene/isoprene copolymer and is provided with good properties including low permeability to gases, good thermal stability and high resistance to oxygen and ozone action, among others. It is well known that the end-use rubber properties depend on the state of cure distribution in the rubber products. This work aimed to predict the state of cure in vulcanization process of butyl rubber by the finite element simulation based on a new characterization model. For describing the cure state, the new characterization model of curing degree was developed, which was implemented in finite element simulation model by the secondary development of ABAQUS software subroutine UVARM. To improve the accuracy, the vulcanization reaction heat was also considered, which was implemented by the subroutine HETVAL. Results indicated that the predicated results of curing degree based on the simulation model are according to the experiments. The model can be well distinguished the curing stages and its degree, such as under curing, positive curing, over curing. It would give a valuable guide for optimizing the vulcanization processing of butyl rubber or other vulcanized rubbers.
The Effect of Polyethylene Terephthalate Particle Size and Concentration on the Properties of Asphalt and Bitumen as An Additive
Authors: Maharaj Chris , Maharaj Rean , Maynard Julian
Published: September 2018

Research is extremely limited on the combination of polymeric materials, such as discarded polyethylene terephthalate (PET), with asphaltic materials indigenous to Trinidad and Tobago. This paper examines the effect of both concentration and particle size of added PET on the rheological properties of Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB). The PET particle size ranges under study were >0.30 mm to 0.60 mm, >0.60 mm to 0.85 mm, and >0.85 mm to 1.18 mm. These particle sizes were added in concentrations by weight ranging from 2% to 8% PET for TPB and 2% to 4% PET for TLA.

Incorporating the waste polymeric material PET in TLA and TPB influenced the physical properties of the resulting blends. For TLA-PET blends, the largest particle size range produced values of complex shear moduli that were higher than pure TLA. The smallest particle size range had the opposite effect. The optimal concentration for fatigue cracking and rutting resistance occurred at 2% PET with the largest particle size range.

For TPB-PET blends, the peak value of complex shear modulus generally occurred at concentrations above pure TPB for all particle size ranges and temperatures tested. As the particle size range increased, these peak values occurred at lower concentrations of PET. The 2% concentration for the largest particle size range provided the best fatigue cracking resistance, whereas the particle size range >0.60 mm to 0.85 mm produced the best rutting resistance.

This study demonstrated that incorporating waste PET as an additive in road paving mixtures could improve the overall quality of roads and also be a sustainable waste disposal option. Further research is recommended on the effect of PET particle size range and concentrations on TLA/TPB combinations commonly used in road paving applications along with accelerated weathering studies.
Effect of Latex and Accelerator on the Strength Development and Chloride Ion Penetration Properties of Latex-Modified Repair Concrete
Authors: Jeon Ji-Hong , Cha Sang-Sun , Park Chan-Gi
Published: September 2018

The objective of this study was to evaluate the effect of the amount of added latex and accelerator on the strength development and chloride ion penetration properties of concrete used for the repair of concrete pavement. Such pavement must be re-opened to traffic 3 days after repairing. The target values of the latex-modified repair concrete were as follows: a compressive strength of 22 MPa and a flexural strength of 4.5 MPa after 3 days, and a compressive strength of 27 MPa and chloride ion penetration value of < 2,000 coulombs after 28 days. In this study, latex was added at 0, 5, 10, and 15% of the cement weight, and the accelerator was added at 0 and 1% of the cement weight. The test results indicated that the mixes with accelerator and latex contents of 10 and 15% satisfied the target strength and chloride ion penetration values for the 3-day traffic opening requirement.
Biodegradation of Low Density Polyethylene (Ldpe) by Mangrove Fungi from the Red Sea Coast
Authors: Ameen Fuad , Moslem Mohammed , Hadi S. , Al-Sabri Ahmed E.
Published: September 2018

Forty five fungal isolates belonging to 13 genera were derived from tidal water, floating debris, and sediment collected from mangrove stands on the Red Sea coast of Saudi Arabia. Six of these isolates and their consortium were found to be able to grow in association with low density polyethylene (LDPE) film under in vitro conditions in the absence of dextrose or any other carbon source. These isolates were further tested for their potential to degrade LDPE by co-cultivation under aeration on a rotary shaker. Examination under light and scanning electron microscope revealed that the fungi attached themselves to the surface of the film and grew profusely. As compared to the controls, these fungi accumulated significantly higher biomass, produced more ligninolytic enzymes, and released larger volumes of CO2 during co-cultivation with LDPE. These observations indicated that the selected isolates were able to breakdown and consume the LDPE film.
Physical Properties of Low Density Polyethylene, Polyvinylchloride and Used Engine Oil Modified Asphalt
Authors: Maharaj Rean , Maharaj Chris
Published: September 2018

Since the influence of polymeric additives on the rheological and performance characteristics of bituminous materials is dependent on the composition and origin of the bituminous base materials itself, the influence of polymeric additives on the physical properties of the world renowned Trinidad Lake Asphalt (TLA) was investigated. The specific physical, performance properties of rutting resistance and fatigue cracking resistance (as measured by the rheological properties of complex modulus and phase angle) and viscosity of Trinidad Lake Asphalt modified with varying levels of waste Low Density Polyethylene (LDPE), Polyvinyl Chloride (PVC) and Used Engine Oil (UEO) were measured to deduce the applicability of these waste polymeric materials as a performance enhancer for the base asphalt. The results indicated that as the UEO concentration in TLA increased (0–30%), there was an incremental increase in the fatigue cracking resistance and a decrease in rutting resistance. The incremental addition of PVC to TLA (0–10%) resulted in optimal rutting resistance at 2% and 8% PVC concentrations respectively. The fatigue cracking resistance and rutting resistance of the LDPE modified TLA increased with the addition of 1% LDPE; further additions having minimal effect on the performance properties of the blends. Viscosity measurements at different temperatures of the various polymer-asphalt blends were made to determine the ease at which the blends can be mixed during the manufacturing process.
Structure – Property Relationships in Microcrystalline Waxes for Museum Seismic Protection Applications
Authors: Laefer Debra F. , Kennedy James E. , O'Flynn Kevin P. , Stanton Kenneth T.
Published: September 2018

The application of microcrystalline waxes to the bases of art objects is an inexpensive method to provide protection from earthquakes and other ground-borne vibrations. In this paper, four microcrystalline waxes that were developed and/or marketed for art object protection are analysed using Fourier transformed infrared spectroscopy, X-ray diffraction, confocal laser scanning microscopy, differential scanning calorimetry, and dynamic rheological analysis. Results from each analysis are compared for each wax and from previously published sources. Findings are considered with respect to previously published mechanical testing performance, in regards to their potential appropriateness for art object protection. In particular, the glass transition temperatures of two of the waxes, as determined by dynamic rheological analysis, are approximately 35°C. This indicates that these two waxes may be unsuitable for museum usage, if ambient temperatures reach these levels.
Application of Polymer Based Composite Materials in Transportation
Authors: Koniuszewska Anna G. , Kaczmar Jacek W.
Published: September 2018

The purpose of this paper is to present the latest applications of fibre-reinforced polymer matrix composites described on exemplary applications. It contains the description of various examples, which were classified into the following categories: aerospace, automotive, marine, military and sport and leisure industry.
The Effect of Different Chemical and Physical Processing on the Physicochemical and Functional Characterization of Chitosan Extracted from Shrimp Waste Species of Indian White Shrimp
Authors: Nouri Marjan , Khodaiyan Faramarz , Razavi Seyed Hadi , Mousavi Mohammad Ali
Published: September 2018

The preparation and characterization of chitosan, water soluble polysaccharide, from waste of Indian white shrimp (penaeus indicus) are reported. The effect of different conditions of chemical and physical methods on extraction, physiochemical (proximate composition, solubility, degree of deacetylation and molecular weight) and functional properties (fat binding capacity, water binding capacity and color attributes) of biopolymer chitosan was examined. The results suggested that optimal condition preparation involves alkali concentration of 50%, a power of microwave of 720 W and a reaction time of 20 S. The end product had a white color, high degree of deacetylation, solubility and low molecular weight, ash, protein and moisture content.
Effect of Dopant Type on the Properties of Polyaniline Filled PU/PMMA Conducting Interpenetrating Polymer Networks
Authors: Naseem Sajid , Irfan Muhammad Shafiq , Saeed Farhan , Manzoor Muhammad Bilal , Qaiser Asif Ali , Shehzad Muhammad Aamir
Published: September 2018

The primary aim of the research reported in this paper is to study the influence of the type of dopant, used in the synthesis of polyaniline, on the physico-mechanical and electrical properties of polyaniline filled composites. Polyaniline (PAni) doped with four different dopants was used as a filler in the interpenetrating polymer networks (IPNs) of polymethyl methacrylate (PMMA) and polyurethane (PU). The dopants used in the synthesis of PAni included inorganic dopants (hydrochloric acid (HCl), sulphuric acid (H2SO4)) and organic dopants (p-Toluenesulfonic acid (PTSA), camphor sulphonic acid (CSA)). Physico-mechanical properties of the filled-IPNs, tensile strength, hardness, elongation at break and Young's modulus were determined along with electrical conductivity. Chemical resistance of the IPNs against different acids and bases was also determined. It was observed that the properties of PAni filled PU/PMMA IPNs were a strong function of the type of dopant used in the synthesis of PAni.
Characteristics of Pyrolysis Products from Waste Tyres and Spent Foundry Sand Co-Pyrolysis
Authors: Perondi Daniele , Scopel Bianca Santinon , Collazzo Gabriela Carvalho , Silva Jayna Pessutto , Botomé Michele Leoratto , Dettmer Aline , Godinho Marcelo , Vilela Antônio Cesar Faria
Published: September 2018

The products obtained through thermal conversion of tyres can represent a solution for its disposal which has been considered an environmental problem. In the foundry industry two types of sand are generated: core sand (CS) and green sand (GS); CS is classified as hazardous waste. In this paper two kinds of industrial wastes were approached, in order to propose a solution through co-pyrolysis. The experiments were performed in a bubbling fluidized bed reactor. The oil, fuel gas and char obtained were characterized. The main components present in the oil were naphthalene and anthracene. Char morphology was assessed by Scanning Electron Microscopy, confirming the resin absence on its surface. Isothermal adsorption and desorption indicated that the char obtained from tyre pyrolysis with lower particles has higher superficial area (higher than 200 m2·g−1). The main compounds identified in fuel gas were hydrogen, carbon monoxide, carbon dioxide and hydrocarbons up to 5 carbons.
Transform Rice Husk and Recycled Polyethylene into High Performance Composites: Using a Novel Compatibilizer to Infiltratively Enhance the Interfacial Interactions
Authors: Hong Haoqun , Li Xuesong , Liu Hao , Zhang Haiyan , He Hui , Xu Huanxiang , Jia Demin
Published: September 2018

Rice husks are the fine crop residue used to prepare the industrial wood-like products by melt-blending with polymers. However, most wood-like products are highly filled with natural fibers in order to decrease the cost of the products, as it causes weak interfacial compatibility between the natural fibers and polymers. To successfully prepare a high performance wood-like product, the interfacial compatibility is the key problem that need to be solved. Moreover, the interfacial interactions at the gaps and voids around the natural fibers can enhance the interfacial compatibility of the composites. There is little research focusing on the interfacial interactions at these gaps and voids. In this paper, the multi-monomer graft copolymers of polyethylene (GPE) were used as the compatibilizers for the rice husk (RH) highly filled recycled polyethylene (rPE) composites. How the GPE affected the interfacial compatibility of the composites and the resulting mechanical properties, water resistance, thermal stability and rheological properties of rPE/RH composites were investigated. Results show that GPE could enhance the interfacial interactions of rPE/RH composites by infiltrating into the gaps and voids around RH. The strong interfacial interactions of the composites primarily came from the chemical reactions and physical interactions between RH and GPE. The mechanical properties, water resistance and thermal stability of the composites increased with the increase in GPE loadings. The preferable loadings of GPE were approximately at 8 phr. Meanwhile, GPE could improve the processing properties of the composites.
High Density Polyethylene Degradation Followed by Closed-loop Recycling
Authors: Benoit Nathalie , González-Núñez Rubén , Rodrigue Denis
Published: September 2018

The objective of this work is to investigate the loss of performance undergone by a polymer during a long-term closed-loop recycling process. High density polyethylene (HDPE) is subjected up to 50 extrusion cycles under constant processing conditions. The effect of recycling is then determined by following its degradation with increasing number of generation. After selected cycles, the material is characterized in terms of physical (density, GPC), thermal (DSC, TGA), and mechanical (tension, flexion) properties. No significant change are observed in density, DSC, and TGA tests. But for GPC, the weight average molecular weight (Mw) is found to decrease while the number average molecular weight (Mn) do not change significantly, thus leading to a decreasing polydispersity index. Intrinsic viscosity also decreases, while melt flow index (MFI) increases. From the tensile stress-strain curves, recycling seems to have no significant effect on Young's modulus (Ey), but a moderate increase of the strain at yield is observed followed by a slight decrease, while the stress at yield decreases. For the break-up conditions, stress and energy at break are found to increase significantly. Finally, three-point bending tests show that the flexural modulus (Eb) decreases with recycling. Overall, the recycling process leads to an important modification of the polymer's mechanical properties mainly due to chain scission.
High Precision Optics for LED Applications Made of Liquid Silicone Rubber (LSR)
Authors: Hopmann Christian , Röbig Malte
Published: September 2018

Light Emitting Diodes (LED) conquer the growing global market of lighting technologies. Due to their advantages regarding efficiency and lifetime, they are increasingly used in consumer products, for lighting applications in the home and in the mobility sector as well as in industrial applications. Conventionally, LED chips are encapsulated by so-called primary optics and the optical function is given by an optical head. In the context of a joint research project in cooperation with the partners Hella KGaA Hueck & Co., Lippstadt, Momentive Performance Materials GmbH, Leverkusen, all Germany, and ELMET Elastomere Produktions- und Dienstleistungs-GmbH, Oftering, Austria, an injection molding process of combined primary optics and optical heads made of liquid silicone rubber (LSR) was investigated. Due to the material-specific advantages of highly transparent LSR especially regarding the excellent high temperature resistance and the great freedom in design the optics can meet both the requirements for the encapsulation of LED chips as well as the realization of an optical function. An integrated injection mold concept was realized in order to reduce mounting steps, where a LED circuit-board is inserted and directly overmolded with LSR. Processing studies have shown that a reproducible replication of LSR optics with good optical properties and molding accuracy is possible. Moreover, for the use in an automotive application long term properties are crucial. Therefore, a temperature cycling test between −40°C and 125°C for 1,000 cycles as well as a continuous operation of the LED with permitted maximum current for 2,000 h were carried out.

Additionally, the application of optical micro structured LED optics made of LSR was examined. For this purpose appropriate optics and mold inserts were designed and manufactured.
Polymer Recovery through Selective Dissolution of Co-mingled Post-Consumer Waste Plastics
Authors: Kannan P. , Lakshmanan G. , Shoaibi A. Al , Srinivasakannan C.
Published: September 2018

It still remains a challenge to the recycling industry to develop an efficient and economical large-scale plastic waste recycling system, in spite of growing environmental concerns in waste disposal. Selective dissolution and precipitation (SDP) is a mechanical recycling technique that eliminates pre-sorting of mixed waste plastics and recycling polymer of high-grade quality. In this preliminary investigation, recycling of a comingled post-consumer waste plastic mixture of low-density polyethylene (LDPE), polystyrene (PS), high-density polyethylene (HDPE), and polyethylene terephthalate (PETE) using a lab-scale SDP setup was examined. A few experimental runs performed on the representative samples using Xylene/Toluene as solvents and acetone/2-propanol as anti-solvents demonstrated the sorting and recycling efficiency of this technique. FT-IR analysis of the reclaimed products revealed that the structural properties being very similar to virgin materials.
Rigid Amorphous Phase: Mechanical and Transport Properties of Nitrile Rubber/Clay Nanocomposites
Authors: Thomas Saliney , George Soney C. , Thomas Sabu
Published: September 2018

The present study has been focused on the preparation of nitrile rubber/ organoclay nanocomposites containing 0–10 wt% Cloisite 93A by mechanical mixing on a two-roll mill. The rubber samples were vulcanized by accelerated sulfur vulcanization process. The role of nanoclay on the curing process has been carefully studied. The clay dispersion in the rubber matrix was analyzed by high resolution transmission electron microscopy (TEM) and X-ray diffraction studies. Both XRD and electron microscopic analyses indicated that the nanocomposites exhibit partly intercalated and exfoliated structure. However, the nanocomposites showed better exfoliation at lower clay loading (2 wt percent) as evident by TEM and XRD. At higher clay loading the clay tend to form aggregates. The correlation distance and the length and thickness of the clay platelets in the rubbery matrix have been deduced from the TEM micrographs as a function of clay loading. The nanoclay-rubber interaction has been quantified by Kraus analysis. The nanocomposites exhibited improved mechanical properties which include tensile strength, modulus, tear strength and resistance to abrasion. The solvent resistance of the nanocomposite increased with the increase in dosage of the nanofiller. Finally, the properties have been modeled using Guth and Halpin-Tsai equations.
Mechanical and Damping Properties of Wood Plastic Composite Modified by Ground Waste Rubber Tire
Authors: Luo Jianlin , Li Qiuyi , Shang Huaishuai , Gao Song , Zhang Chunwei , Sun Shengwei
Published: September 2018

Recycled WPC product using in construction industry occasionally falls short of expectation owing to lack of sufficient ductility and damping capacity, ground waste rubber tire (WTR) with substantial elasticity can be a proper candidate to meet the gap when adding appropriately. Here, WTR after alkali activation was blended in waste wood flour (WWF) treated with compatibilizer, the mixture after oven-dried was subsequently filled into thermoplastic recycled polyethylene (RPE) or polypropylene (RPP) base (WTR/WPC) through hot-press molding process. Mechanical properties (tensile strength ft, flexural strength fb, impact strength fa) of RPE-based and RPP-based WTR/WPC strips with 4 different WTR fractions were characterized. Its damping properties (loss factor β) were measured and identified by ultrasonic agitation and half-power bandwidth identification method, respectively. The coarse WTR has balanced but stable effect on the improvement of ft, fb, fa, and β of WTR/WPC with rigid RPP base than that with flexible RPE, which attributes to the synthetic effects of good deformation capacity of coarse WTR themselves, strong bridging capacity of WWF, and sufficient stick-slip intercalation between WWF or WTR and rigid RPP. The ft, fb and fa, β with 5% coarse WTR of RPP-based WTR/WPC reaches 12.32 MPa, 15.74 MPa; 2.58 MPa and 0.0853, respectively.
Study on the Application Properties of WPU and OMMT in RTV Mold Rubber
Authors: Siyuang Yang , Jincheng Wang , Junhua Wang
Published: September 2018

The purpose of this work was to research on the application properties of waterborne polyurethane (WPU) and organic montmorillonite (OMMT) in room-temperature-vulcanizated silicone rubber (RTV) used as mold materials.

The first part dealt with the application of WPU in RTV matrix. The composite with 3% WPU showed the highest tensile strength and elongation at break, 4.1 MPa and 1441%, respectively. These properties were improved about 28% and 55% compared with that pure RTV. The COLE and COVE of RTV/WPU-3 was 0.2×10−4∼1.2×10−4K−1 and 2.7×10−3∼4.4×10−3K−1, respectively. These values were lower compared with that of pure RTV.

The second part dealt with the application of OMMT in RTV/WPU composites. When 3% OMMT was added, the tensile strength and elongation at break were increased to 5.6 MPa and 1534%, respectively. The COLE and COVE of RTV/WPU-3/OMMT-7 was 0.32×10−4∼0.94×10−4 K−1 and 0.32×10−3∼2.3×10−3K−1. These values showed an obvious decrease compared with that of RTV/WPU-3 composite. After the addition of 3% OMMT, the acid and alkali resistance of these composites were improved. X-ray diffraction (XRD) and scanning electron microscope (SEM) were also used in the investigation of the microtopography of these RTV composites.
Effect of Silica Phase on Certain Properties of Natural Rubber Based Composites Reinforced by Carbon Black/Silica Hybrid Fillers
Authors: Al-Ghamdi Ahmed A. , Al-Hartomy Omar A. , Al-Solamy Falleh R. , Dishovsky Nikolay , Zaimova Diana , Malinova Petrunka
Published: September 2018

The paper reports on the effect that the silica phase has upon certain characteristics of hybrid fillers obtained via impregnation of two completely different types of conventional carbon black, namely oil absorption number, iodine adsorption, specific surface area, etc. The article also presents their dynamic mechanical and electrical properties, as well as the homogeneity of natural rubber based composites comprising those fillers. It has been found that, the silica phase, depending on its amount (3 or 7%), changes considerably both the main characteristics of the fillers (ash content, specific surface area, oil absorption number, iodine adsorption number, etc.) and their thermal behaviour. The increase in the amount of silica phase leads to a decrease of the storage modulus, while the mechanical loss angle tangent increases during the transition from the glass into rubbery state. The changes in those parameters are related first of all to the changes in the elastomer-filler and filler-filler interactions, to the mobility of elastomer chains and to the relaxation processes. The higher silica content, the higher the surface and volume resistivity of the composites are. On the other hand, the fillers homogeneity worsens depending on the grade of silica phase dispersion along the hybrid filler.
Effect of ZnO Nanoparticles on the Simultaneous Improvement in Curing and Mechanical Properties of NR/ Recycled EPDM Blends
Authors: Hayeemasae Nabil , Rathnayake W.G.I.U. , Ismail Hanafi
Published: September 2018

Recycling of rubber waste and searching for alternative routes to decreasing the loading of ZnO are of significant concern due to their input on environmental aspect. In this respect, recycled ethylene-propylene-diene (EPDM) rubber has been used in an attempt to create a value-added rubber material based on natural rubber/recycled EPDM blends. ZnO nanoparticles were also incorporated as a way to replace the conventional ZnO together with the aim of improving the curing and mechanical properties of the blends. Spherical and elongated shapes of ZnO nanoparticles were synthesised by a homogeneous precipitation method and were then characterised by Transmission Electron Microscopy (TEM) and X-Ray diffraction analysis. Synthesised ZnO nanoparticles were found to have no impurities and had a dimension ranging from 10–40 nm. The study confirmed that ZnO nanoparticles showed a better state of curing and higher maximum torque with a significant decrease in optimum curing time and scorching time. It was also observed that a low content of ZnO nanoparticles was sufficient to give higher mechanical properties compared to one containing a higher content of conventional ZnO.
Performance of Waste Polymer Modified Road Paving Materials
Authors: Maharaj Rean , Maharaj Chris , Hosein Areo
Published: September 2018

The reuse of waste crumb rubber (CR) (used tyres) and Polyethylene Terephthalate (PET) (plastic beverage bottles) is of particular interest in Trinidad and Tobago since present disposal techniques presents environmental and health challenges. The results of this study investigating the influence of PET and CR on the performance characteristics of the HMA2 pavement design using Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) filled an information gap as no previous studies utilizing these indigenous asphaltic materials exist. Existing information using asphaltic materials other than TLA and TPB are irrelevant as variations in performance characteristics due to the addition of polymeric additives can vary from asphalt to asphalt due to differences in source and chemical composition of the parent binder. The results of this study show that a 6% CR and PET addition achieved the highest performance advantage demonstrated by an increase in the Marshall Quotient of between 21–22% and an insignificant decrease in the Bulk Specific Gravity (0.2%) compared to the unmodified blend. The improvement in the mechanical properties and the performance of the modified pavement materials observed is evidence of the useful effects of these waste materials in road paving design and offer a beneficial strategy for the reuse of these waste materials.
Effect of Starch Nanocrystals on Natural Rubber Latex Vulcanizate Properties
Authors: Anand K , Varghese Siby , Kurian Thomas , Bose Suryasarathi
Published: September 2018

The incorporation of bio-nanofillers such as starch nanocrystals (SNC) in polymer matrices received much attention owing to their biodegradable nature. In this work, starch nanocrystals have been isolated from modified corn starch by acid hydrolysis and their efficacy as a potential bio-filler for natural rubber latex (NR) has been explored. The quality of the SNC suspension was confirmed from dynamic light scattering (DLS) studies and X-ray diffraction (XRD) measurements. For the fabrication of nanocomposites of NR with corn starch crystals, a simple latex stage mixing procedure was employed. The platelet-like morphology of corn starch nanocrystals improved the barrier properties of NR based vulcanizates with the addition of the SNC suspension.
Defining and Measuring Sustainability in the Food & Fitness Initiative
Authors: Quinn Martha , Kowalski-Dobson Theresa , Lachance Laurie
Published: September 2018

Several frameworks for defining and measuring sustainability in public health have been documented in the literature. For the Food & Fitness Initiative, sustainability was a central aim at the outset and was defined broadly throughout the project. Sustainability included not only funding and resources necessary to support organizational structures but was a core function of how these partnerships were able to focus their work, build capacity, forge lasting relationships, execute the work, and produce systems and policy changes that would endure over time. In this article, we present findings from an online survey assessing partners’ views on 10 distinct dimensions of sustainability and several key themes from a set of key informant interviews with partnership leaders. Of the 10 dimensions, participants reported having the most success in creating (1) community ownership, where initiatives are led by and reflect the needs of community residents; (2) a vision that is shared across partners and developed collaboratively; and (3) leadership that includes a diverse team of skilled, credible people. A key learning in this project was that sustainability needs to be intentional and clearly defined and that evaluations should include multiple and ongoing methods to capture several dimensions of sustainability.
Prioritizing Racial Equity: How Efforts to Advance Racial Equity Helped Shape the W.K. Kellogg Food & Fitness Initiative
Authors: Lee Mary M. , Navarro Amanda
Published: September 2018

Racial equity is closely linked to principles of fairness and justice. It is distinct from the concept of racial equality. Community engaged strategies aimed at creating racial equity have generated effective ways to dismantle structural racism—the racialized policies and practices that have shaped economic and social institutions in the United States throughout its history. In crafting the Food & Fitness Initiative, the W.K. Kellogg Foundation made advancing racial equity a top priority. By doing so, it encouraged the community partnerships funded under the initiative to apply theories of expanding equity to real-world situations in order to reduce racial disparities in their neighborhoods. This article reviews the methods that were employed over the course of the initiative to support the partnerships with their efforts. It highlights three key components: (1) being intentional about maintaining a focus on racial equity, (2) concentrating on changing policies and systems, and (3) consistently incorporating meaningful and authentic community engagement into the work. The importance of making the concept of equity concrete and measurable is explored. Furthermore, the article discusses strategies that strengthened the capacity of the partnerships to navigate the policy-making process and to build leadership and shift power to community residents. The article concludes by detailing measures that could guide future efforts to make racial equity a priority and emphasizes that doing so is crucial given the rapid demographic shifts underway across the country.