Assessing effects of thermoset polyester resin waste powder on the processing and mechanical properties of natural rubber

Products made of glass fibre reinforced polymers are often disposed of in landfill, incinerated or processed into waste powders at the end of their service life. Waste powders can be recycled as fillers for use in virgin polymers. The effects of up to 50 parts per hundred rubber by weight thermoset polyester resin waste powder on the viscosity, cure and mechanical properties of a sulphur-cured natural rubber compound were studied. The powder had resin polymer particles and glass fibre fragments ranging from approximately a few microns to 700 microns in size. The viscosity remained unchanged and the cure properties deteriorated when the powder was added to the rubber. The hardness, Young’s modulus and tensile modulus increased whereas, the tensile strength, elongation at break, stored energy density at break and tearing energy decreased. There was also evidence of poor adhesion between the powder and rubber. It was concluded that the waste powder could be recycled as an extender filler to replace a portion of the raw rubber in the compound

Characterisation and use of glass fibre reinforced plastic waste powder as filler in styrene-butadiene rubber

Glass fibre reinforced plastic (GRP) wastes are often disposed of in landfill, incinerated or processed into powders. GRP waste powders can be recycled as filler in virgin polymers and should be characterised before they are added to avoid processing problems. A GRP waste powder was characterised using advanced measuring and analytical techniques. These included, scanning electron microscopy, Fourier transform infrared spectrometry, particle size analyser, differential scanning calorimetry, X-ray photo-electron spectroscopy and energy dispersive X-ray microanalyser. The results showed that the waste powder consisted of irregular shaped particles and glass fibre fragments up to 700 m in size. Moreover, the waste powder was a thermoset polyester resin and its chemical constituents were calcium, oxygen, aluminium, silica, chlorine, bromine and carbon. When up to 25 parts per hundred rubber by weight of the GRP waste powder was mixed with a sulphur cure- based styrene-butadiene rubber, the viscosity, scorch and optimum cure times increased, and the rate of cure decreased. The tearing energy, elongation at break, tensile strength, stored energy density at break, and Young’s modulus of the vulcanisate improved as the loading of the waste powder was raised

Characterisation and use of glass fibre reinforced plastic waste powder as filler in styrene-butadiene rubber

Glass fibre reinforced plastic (GRP) wastes are often disposed of in landfill, incinerated or processed into powders. GRP waste powders can be recycled as filler in virgin polymers and should be characterised before they are added to avoid processing problems. A GRP waste powder was characterised using advanced measuring and analytical techniques. These included, scanning electron microscopy, Fourier transform infrared spectrometry, particle size analyser, differential scanning calorimetry, X-ray photo-electron spectroscopy and energy dispersive X-ray microanalyser. The results showed that the waste powder consisted of irregular shaped particles and glass fibre fragments up to 700 m in size. Moreover, the waste powder was a thermoset polyester resin and its chemical constituents were calcium, oxygen, aluminium, silica, chlorine, bromine and carbon. When up to 25 parts per hundred rubber by weight of the GRP waste powder was mixed with a sulphur cure- based styrene-butadiene rubber, the viscosity, scorch and optimum cure times increased, and the rate of cure decreased. The tearing energy, elongation at break, tensile strength, stored energy density at break, and Young’s modulus of the vulcanisate improved as the loading of the waste powder was raised

Using a sulfur-bearing silane to improve rubber formulations for potential use in industrial rubber articles

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Adhesion Science and Technology on 13/08/2012, available online: http://dx.doi.org/10.1080/01694243.The availability of the coupling agent bis (3-triethoxysilylpropyl)-tetrasulfide (TESPT) has provided an opportunity for enhancing the reinforcing capabilities of precipitated amorphous white silica in rubber. Styrene-butadiene rubber, synthetic polyisoprene rubber (IR), acrylonitrile-butadiene rubber, and natural rubber (NR) containing the same loading of a precipitated silica filler were prepared. The silica surface was pretreated with TESPT, which is a sulfur-bearing bifunctional organosilane to chemically bond silica to the rubber. The rubber compounds were subsequently cured by reacting the tetrasulfane groups of TESPT with double bonds in the rubber chains and the cure was optimized by adding sulfenamide accelerator and zinc oxide. The IR and NR needed more accelerators for curing. Surprisingly, there was no obvious correlation between the internal double bond content and the accelerator requirement for the optimum cure of the rubbers. Using the TESPT pretreated silanized silica was a very efficient method for cross-linking and reinforcing the rubbers. It reduced the use of the chemical curatives significantly while maintaining excellent mechanical properties of the cured rubbers. Moreover, it improved health and safety at work-place, reduced cost, and minimized damage to the environment because less chemical curatives were used. Therefore, TESPT was classified as "green silane" for use in rubber formulations

Cardio-metabolic and socio-demographic risk factors associated with dependency in basic and instrumental activities of daily living among older Iranian adults: Bushehr elderly health program

Background: Iran’s population is aging. Disability is a major public health problem for older adults, not only in Iran but all over the world. The purpose of this study was to investigate the relationship between cardio-metabolic and socio-demographic risk factors and disability in people 60 years and older in Iran. Methods: The baseline (cross-sectional) data of 2426 samples from the Bushehr Elderly Health (BEH) program was included in the analysis. The participants were selected through multi-stage random sampling in Bushehr, southern Iran. Socio-demographic characteristics, as well as the history of diabetes and other chronic diseases, and smoking were measured using standardized questionnaires. Anthropometric measurements and laboratory tests were performed under standard conditions. Dependency was determined by the questionnaires of basic activities of daily living (BADL) and instrumental activities of daily living (IADL) using Barthel and Lawton scales respectively. Multiple logistic regression was used in the analysis. Results: Mean (Standard Deviation) of the participants’ age was 69.3 (6.4) years (range: 60 and 96 years), and 48.1% of the participants were men. After adjusting for potential confounders, being older, being female (OR (95%CI): 2.3 (1.9–2.9)), having a lower education level, a history of diabetes mellitus (OR: 1.4 (1.2–1.7)) and past smoking (OR: 1.3 (1.0–1.6)), and no physical activity (OR: 1.5 (1.2–1.9)) were significantly associated with dependency in IADL. Also, being older and female (OR: 2.4 (1.9–3.0)), having a lower education level, no physical activity (OR: 2.2 (1.6–2.9)) and daily intake of calories (OR: 0.99 (0.99–0.99)) were associated with dependency in BADL. Conclusion: Dependency in older adults can be prevented by increasing community literacy, improving physical activity, preventing and controlling diabetes mellitus, avoiding smoking, and reducing daily calorie intake

Acrylamide formation and quality properties of chitosan based batter formulations

[EN] The potential of chitosan to mitigate acrylamide formation has been already demonstrated. The two main objectives of this study were: 1) to select the most adequate degree of deacetylation (DD) and molecular weight (Mw) of chitosan based on acrylamide mitigation criteria and 2) to evaluate the influence of including chitosan in batter formulations on some important technological parameters of raw batters (flow behavior and water retention capacity) and on some quality properties of fried batters (oil uptake, color and texture). Results in model systems showed that chitosans with higher deacetylation degree (86.5 and 92.8%) achieved a decrease of acrylamide between 44 and 81%, depending on reaction time, compared to the control (without chitosan). Furthermore, acid hydrolysis process of chitosan was found to negatively affect its inhibitory effect on acrylamide formation independently of the molecular weight. Raw chitosan based batter formulations presented higher consistency and water retention capacity than the control; chitosan addition to batters reduced the hardening of the fried samples during the post-frying cooling period. No significant differences in water loss were observed between batters with or without added chitosan; however, chitosan-batter formulations showed lower oil uptake during frying as compared to control samples.The authors thank the gs1:Universitat Politecnica de Valencia for the PhD scholarship given to Mariola Sansano Tomas.Sansano Tomás, M.; Castelló Gómez, ML.; Heredia Gutiérrez, AB.; Andrés Grau, AM. (2016). Acrylamide formation and quality properties of chitosan based batter formulations. Food Hydrocolloids. 66:1-7. doi:10.1016/j.foodhyd.2016.10.019S176

Safety and efficacy of Favipiravir in moderate to severe SARS-CoV-2 pneumonia

Background: We examined the safety and efficacy of a treatment protocol containing Favipiravir for the treatment of SARS-CoV-2. Methods: We did a multicenter randomized open-labeled clinical trial on moderate to severe cases infections of SARS-CoV-2. Patients with typical ground glass appearance on chest computerized tomography scan (CT scan) and oxygen saturation (SpO2) of less than 93 were enrolled. They were randomly allocated into Favipiravir (1.6 gr loading, 1.8 gr daily) and Lopinavir/Ritonavir (800/200 mg daily) treatment regimens in addition to standard care. In-hospital mortality, ICU admission, intubation, time to clinical recovery, changes in daily SpO2 after 5 min discontinuation of supplemental oxygen, and length of hospital stay were quantified and compared in the two groups. Results: 380 patients were randomly allocated into Favipiravir (1 9 3) and Lopinavir/Ritonavir (1 8 7) groups in 13 centers. The number of deaths, intubations, and ICU admissions were not significantly different (26, 27, 31 and 21, 17, 25 respectively). Mean hospital stay was also not different (7.9 days SD = 6 in the Favipiravir and 8.1 SD = 6.5 days in Lopinavir/Ritonavir groups) (p = 0.61). Time to clinical recovery in the Favipiravir group was similar to Lopinavir/Ritonavir group (HR = 0.94, 95% CI 0.75 � 1.17) and likewise the changes in the daily SpO2 after discontinuation of supplemental oxygen (p = 0.46) Conclusion: Adding Favipiravir to the treatment protocol did not reduce the number of ICU admissions or intubations or In-hospital mortality compared to Lopinavir/Ritonavir regimen. It also did not shorten time to clinical recovery and length of hospital stay. © 2021 Elsevier B.V

Optimising silanes in silica-filled rubber products

Optimising silanes in silica-filled rubber product

Assessing the Effect of Thermoset Polyester Resin Waste Powder on the Processing and Mechanical Properties of Natural Rubber

Products made of glass fibre reinforced polymers are often disposed of in landfill, incinerated or processed into waste powders at the end of their service life. Waste powders can be recycled as fillers for use in virgin polymers. The effects of up to 50 parts per hundred rubber by weight thermoset polyester resin waste powder on the viscosity, cure and mechanical properties of a sulphur-cured natural rubber compound were studied. The powder had resin polymer particles and glass fibre fragments ranging from approximately a few microns to 700 microns in size. The viscosity remained unchanged and the cure properties deteriorated when the powder was added to the rubber. The hardness, Young’s modulus and tensile modulus increased whereas, the tensile strength, elongation at break, stored energy density at break and tearing energy decreased. There was also evidence of poor adhesion between the powder and rubber. It was concluded that the waste powder could be recycled as an extender filler to replace a portion of the raw rubber in the compoun