Plastic waste generated by the Ecuadorian agro-industrial sector represents one of the main environmental impacts, particularly in floricultural and banana production, as a result of its use as a greenhouse cover and as a protective element for the fruit cluster, respectively. The situation become more complicated because of the level of degradation caused by environmental exposure and the degree of contamination due to the use of agrochemicals that plastics present once their useful life has expired. The current research was divided into two stages: characterization of plastic waste and conditioning prior to reprocessing. The results revealed the plastic waste of the floricultural and banana sector, whose predominant material corresponds to LDPE and HDPE, respectively, presents a level of contamination that allows them to be considered as “non-hazardous” waste, which allows them to be recycled, but their processes must be properly controlled and carried out by qualified people. The level of degradation in the exposed banana bags showed losses of mechanical properties of tensile less than 50%, which means that the material is not degraded and it is feasible to recycle it directly. Additionally, the FTIR-ATR spectra on both sides of the film in the samples did not register representative bands of oxidation. On the other hand, in the greenhouse waste, the losses of mechanical properties of tensile strength above 50% as well as the noticeable formation of carbonyl groups in the structure of the material showed the degradation of the plastic. Therefore, the feasibility of recycling will depend on the incorporation of virgin material. The conditioning of the waste for subsequent recycling revealed the need of a washing process consisting of four stages: initial cleaning, pre-wash, washing, and air-drying.

In natural polyisoprene glove manufacturing industries, the selection of accelerators in the curing system is mainly determined by the curing characteristics, maturation time required, cross-link density and mechanical properties of gloves. In this study, a new accelerator replacing conventional ones in a typical glove manufacturing process, was studied in order to produce free carcinogen dipped article. The glove properties and performance prepared by using both conventional and new proposed accelerators were studied and compared. The use of a conventional accelerator tends to release carcinogenic chemicals namely N-nitrosamine and N-nitrosatable substances. These chemicals are restrained on dipped articles under the requirement of EN 71-12:2013. Xanthogen accelerators promote the reduction of carcinogenic chemicals, but they are associated with prolonged maturation hour, which is unfavourable in the manufacturing industry. This study used a mixture of a benign accelerator, namely, diisononyldithiocarbamate and diisopropyl xanthogen polysulfide, to substitute the usage of conventional accelerators zinc dibutyl dithiocarbamate and zinc diethyl dithiocarbamate. The effects of benign accelerator loading in latex compounds were studied by focusing on the swelling index, maturation hour, carcinogenic chemical released and mechanical properties, thermal degradation and stability. Results showed no presence of N-nitrosamines and N-nitrosatable substances in the final dipped products by using 0.3 and 0.5 phr of benign accelerator. This study showed that 0.5 phr of benign accelerator achieved a moderate pre-vulcanising rate and improved the pre-ageing tensile strength and elongation by 11% and 7.0%, respectively. Moreover, its thermal stability was higher and discolouration intensity was lower as compared with the conventional accelerator.

The demand for gloves (e.g., disposable gloves, medical gloves) is increasing due to the Coronavirus disease 2019 (COVID-19) pandemic. Stability in the supply chain in the glove industry is importa...

In several works, scientific researchers targeted the development of polymeric materials with good mechanical and thermal properties and resist heat and fire propagation. In a new approach, this ar...

Gaining considerable attention as valuable plastic static-dissipative materials, conductive polymer blends are used as supercapacitors, light emitting diodes, artificial muscles and biosensors. The...

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.

An outstanding interest on elimination of nitrosamine generation in traditional sulfur vulcanization systems has led to introduce nitrosamine safe accelerator/s to produce safe natural rubber (NR) vulcanizates. It is an effective way to prevent formation of carcinogenic N-nitroso compounds during manufacture of rubber products. In the present study, behavior of nitrosamine safe binary accelerator system consisting of diisopropyl xanthogen polysulfide (DIXP) with commonly used non-regulated accelerator N-tert-butyl-2-benzothiazole sulfenamide (TBBS) was investigated in efficient sulfur vulcanization of NR. Cure characteristics, physico-mechanical properties and crosslink density of vulcanizates prepared with different combinations of the accelerator system were evaluated and compared with those of individual accelerators. The study reveals that moduli and strength properties of the vulcanizate prepared with DIXP accelerator are inferior to those of the vulcanizate prepared with TBBS accelerator. Nevertheless, optimum cure time of the DIXP compounds is lower in comparison to TBBS compounds. Moreover, progressive replacement of DIXP with TBBS in the accelerator system showed a synergistic effect in regard to cure characteristics and physico-mechanical properties.

Although the consequences of adhesive residues from post-consumer Poly(ethylene terephthalate) (PET) beverage bottles on the performance of recycled products are known, the quantitative effects of ...

In this study, the effect of the simultaneous incorporation of different contents of CaCO3 nanoparticles (NPs) and waste ground rubber tire powder (WGRT) on the forced vibration behavior of polypropylene (PP) was experimentally investigated. Hammer test with modal analysis was performed to investigate the vibrational behavior of the composite plates with one edge clamped (CFFF) support condition. Microstructural assessment of composites using Field Emission Scanning Electron Microscope (FESEM) images showed that a rise in CaCO3 nanoparticles in small weight percentages led to better dispersion and a decline in the tire phase size in the small weight percentage of WGRT. Moreover, a comparison of the modal analysis results revealed that all ternary composites, except in the first mode, had a higher damped natural frequency than pure PP. The damping ratio of all ternary composites, especially in the first and second modes, was higher than pure PP, which is due to the combined effect of WGRT and CaCO3 nanoparticles in increasing energy dissipation and damping of composites.

Considering the application scenarios of rubber granules from waste tires in the bitumen modification process (wet or dry process), both aerobic and anaerobic aging of rubber may occur. The current study aims to investigate the thermal aging behavior of waste tire rubber samples using nanoindentation and environment scanning electron microscopy (ESEM) tests. Both aerobic and anaerobic aging tests with different durations were conducted on rubber samples. The complex moduli of aged rubber samples were measured by nanoindentation tests. The surface morphology and elemental composition of aged samples were obtained by ESEM tests together with the energy dispersive X-ray analysis. Results have shown that for both aerobic and anaerobic aging, the equilibrium modulus derived from the complex modulus curve first increases and then decreases with aging time. However, the time needed for the aerobically aged sample to reach the maximum equilibrium modulus is shorter than the anaerobic case. Aging results in crack propagation and an increase of sulfur content on the rubber surface until it reaches the peak. The degree of crosslinking reflected by sulfur content for anaerobic aging is higher than aerobic aging. The morphological change and elemental change of rubber correlate well with the change of mechanical properties. The aging of rubber from the waste truck tire at 180°C can generally be separated into two stages: crosslinking dominant stage and chain scission dominant stage.

Flame retardant rubber foams of ethylene vinyl acetate (EVA)/natural rubber (NR)/layered silicate blends filled with silicon dioxide (SiO2) were prepared by using azodicarbonamide (ADC) as a blowing agent. Specifically, SiO2 was added in EVA/NR blend nanocomposites to produce good flame retardant foams. The properties of EVA/NR blend nanocomposite foams with different SiO2 loading (0, 20, 30, 40 parts per hundred rubber, phr) were investigated through transmission electron microscopy (TEM), scanning electron microscopy (SEM), rheological property test, mechanical property measurement, flammability tests, thermogravimetry analysis (TGA) and pyrolysis-gas chromatography-mass spectrometry (Pyrolysis-GC-MS). Compared with the simple EVA/NR blend nanocomposite, the added SiO2 increased the blend compatibility between EVA and NR phases and melt strength/viscosity of the EVA/NR blend nanocomposites, thus promoting cellular structure of the EVA/NR nanocomposite foams. Increasing SiO2 loading resulted in higher cell density, smaller cell size, and lower volume of void. These improvements caused higher strength and elastomeric recovery. The LOI test results showed that flame retardancy of the EVA/NR blend nanocomposite foams increased at higher SiO2 loading as a result of formation of insulation silicon dioxide-based char. TGA and pyrolysis-GC-MS analyses also validated the finding that the silicon dioxide-based char in the foamed samples containing higher SiO2 loading was more effective on improving thermal stability, which was responsible for lower material combustibility and better flame retardancy. Based on our finding, it was concluded that a good flame retardant EVA/NR blend nanocomposite foam with the best improvement in strength and elastomeric recovery was achieved when combined with 40 phr SiO2.

The purpose of this study aims at investigating the impact of multi-walled carbon nanotubes (MWCNT’s) on the properties of low viscosity grade asphalt binder. Asphalt binder with viscosity grade-10 is selected as the control binder and later it is modified with different percentages of MWCNT’s (0.5–2.5%). Penetration, softening point, ductility and rotational viscosity test were employed for evaluating the effect of MWCNT’s on basic physical properties of modified asphalt binder. Dynamic Shear Rheometer (DSR) is used for evaluating the rheological properties of the base and modified bitumen, for both aged and unaged bitumen. Based on the conventional and basic rheological tests, it was seen that the addition of MWCNT’s improved the high-temperature performance of modified bitumen. Multiple Stress Creep and Recovery (MSCR) test results revealed that the addition of MWCNT’s improved the creep and recovery of modified binders for both stress intensities (0.1 kPa and 3.2 kPa) which confirms that the modified binder is more rut resistant. Moreover, it was observed that there was a significant improvement in the aging resistance of the asphalt binder due to addition of MWCNTs. However low temperature performance of MWCNTs was not encouraging. Also, MWCNTs addition to asphalt binder was found to be stable under high-temperature storage condition. Overall, there is a significant amount of improvement using MWCNTs in the base asphalt binder.

In this study, the compatibilization effects of triglycidylisobutyl polyhedral oligomeric silsesquioxane (TEpPOSS) on biodegradable poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends were investigated. All blends were prepared via melt blending and PLA/TPU (80/20, 70/30, 50/50 wt%) ratio was selected as the experimental parameter. In order to predict the selective localization of TEpPOSS thermodynamically, wetting coefficient were determined by means of surface energy measurements. Morphological analyses were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, rheological, mechanical, thermomechanical and thermal properties of the blends were performed via rheometer, universal tensile tester, dynamic mechanic analyses and differential scanning calorimeter (DSC), respectively. Morphological test results revealed that TEpPOSSs were mostly located at the interfaces of the PLA and TPU phases. According to the rheological studies, the interfacial interactions between PLA and TPU were improved with the addition of TEpPOSS, which resulted from the potential reactions between epoxy-carboxylic acid and/or epoxy-hydroxyl functional groups. The addition of TEpPOSS enhanced the mechanical properties of PLA/TPU blends. DSC test results revealed a decrease in the glass transition temperatures of PLA in the presence of TEpPOSS, which was an another indication of improved compatibility between PLA and TPU.

The mechanical properties of both radiation (RVNRL) and peroxide vulcanized natural rubber latex (PVNRL) are low when compared to sulphur prevulcanized natural rubber latex (SVNRL). This paper deals with the effect of peroxide on the mechanical properties of radiation vulcanized NR latex film. Here, n-butyl acrylate (n-BA) was used as sensitizer and t-butyl hydroperoxide (t-BHPO) as co-vulcanizing agent during irradiation. It was found that the addition of t-BHPO is more practical method to reduce the vulcanization dose. Thermal ageing study showed that the best retention in tensile properties was shown by RIPV vulcanizates.

Replacement of virgin polymer with its waste become one of the special technique that capture the efforts of many researchers and industrialists alike. In this context, this work discussed the part...

Consumption of coated abrasive discs in various automobile and pipe fitting application is increasing, due to its good surface finish. Coated abrasive disc consists of single layer of abrasive grain bonded to a fibre backing. The major portion of the disc is comprised of fibre backing. But the sustainability of the fibre backing is low and is dumped as waste after usage. The present work deals with the removal of resin coating and recovery of fibre backing from the spent coated abrasive discs using physical separation process such as sand blasting technique. Initially, the recovery experiment was carried out based on L16 orthogonal array. The factors and levels chosen for the experiments were erodent pressure (0.2, 0.4, 0.6 and 0.8 MPa), erodent size (36, 60, 80 and 120 grit), disc orientation (30, 45, 60 and 75°) and number of times flexing (5, 10, 15 and 20). The experimental result shows that erodent size and erodent pressure have a major impact on recovery of the fibre backing. The surface structure of the recovered backing was analysed using scanning electron microscopy and optical microscopy. The recovered backing was very much useful for the coated abrasive industry as the flexible backing and support material for abrasive grain coating.

PVA used in packaging applications has been faced with a UV light degradation challenge, which often reduces its durability while in use. The UV light stability enhancement effect of nanocrystalline cellulose (NCC) reinforcement in PVA was studied. Polyvinyl alcohol composite film was reinforced with NCC from palm oil waste (PVA-NCC film) and exposed to UV light (22 W, SUV-16 254 nm) for different time duration to study the material durability enhancement. The percentage weight loss of the samples was measured to observe the UV light degradation effect. Furthermore, the samples’ structural, morphological, and tensile properties were studied before and after exposure to UV light with FT-IR, scanning electron microscopy (SEM), and tensile test. The results showed physical degradation, morphological and tensile properties enhancement of PVA with NCC’s addition. The addition of NCC to the PVA matrix reduced the degradation rate under UV light significantly. Also, the percentage of weight loss was observed to change with the exposure time to UV light.

Plastic waste has been growing every year, and as a result, environmental concern has been a topic of much attention. Many properties of plastics, such as their lightweight, durability, and versatility, are significant factors in achieving sustainable development. The exponential increase of plastic production produces every year approximately 100 million tons of waste plastic, which could be converted into hydrocarbon fuels by employing a process appropriately called pyrolysis. Pyrolysis, which is thermal or catalytical, can be performed under different experimental conditions that affect the type and amount of product obtained. With the pyrolysis process, products can be obtained with high added value, such as fuel oils and feedstock for new products. In this study, magnesium silicate (MgO3Si) and Cloisite 30B were used as catalysts for the decomposition of different plastics, and the results were compared with the zeolite catalyst. In the case of high-density polyethylene (HDPE), the oil yield with a zeolite catalyst was found to be 71%, whereas with MgO3Si and Cloisite 30B, this was 68% and 67%, respectively. Zeolite produced better results in the decomposition of polypropylene (PP) compared to MgO3Si and Cloisite 30B. Fourier-transform infrared spectroscopy (FTIR), and gas chromatography (GC) were conducted in this work. The spectra results for all samples were consistent and in the fuel range.

A composite material was prepared using epoxy as a matrix, and carbon fiber (20% volume fraction) together with nano titanium dioxide (TiO2) particles in varying weight fractions (0,2,4 and 6%) as hybrid reinforcement. Mechanical tests (impact strength and wear resistance) were carried out, in addition to the study of liquid uptake behavior during immersion in chemical solutions, and inspection with scanning electron microscope imaging to reveal the microscopic details. The results showed that the addition of TiO2 have improved the mechanical properties of the composites, as the specimen reinforced with 4% TiO2 showed the highest impact strength, in addition to improved wear resistance. The scanning electron images for the specimens showed finely dispersed carbon fibers surrounded by the ultrafine TiO2 nano powder, suggesting a uniform distribution of reinforcement throughout the whole matrix for all the prepared specimens. The liquid uptake results showed that the specimen reinforced with 20% carbon fibers and 6% nano TiO2 had the highest diffusion rate, especially when immersed in hydrochloric acid. The results show that the prepared composite could be a good alternative to traditional materials whenever good wear resistance is involved, together with impact and chemical resistance, such as in anti-skid flooring applications.

Lanthanum cerium methionine was synthesized using the metathesis method and its molecular formula was confirmed as La0.35Ce0.65Cl3(C5H10NO2S)3·2H2O via Inductively Coupled Plasma Optical Emission Spectrometer, FTIR, and thermogravimetry-differential scanning calorimetry characterization methods. Lanthanum cerium methionine can significantly reduce the activation energy of the vulcanization reaction. The vulcanization kinetics model is used to fit the vulcanization curve of the rubber, and the obtained vulcanization activation energy of lanthanum cerium methionine for rubber is E1 = 76.89 KJ/mol, E2 = 102.36 KJ/mol and E3 = 126.00 KJ/mol. The above value is lower than pristine rubber. The Kissinger method and Flynn–Wall–Ozawa method were used to analyze the activation energy of thermal-oxidative degradation of vulcanized rubber. It was found that the rubber added with lanthanum cerium methionine exhibited higher thermal-oxidative degradation activation energy compared to that of pristine rubber; in addition, it was more difficult to age under the same environment. These results indicated that lanthanum cerium methionine can be not only used as a vulcanization accelerator, but also plays a role in resisting thermal and oxygen aging.