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Gloves
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Marie-Noëlle Crépy, Pierre Hoerner
Synthetic polyisoprene can be produced chemically, starting from the isoprene monomer, through various polymerization processes (Ziegler Nata, Anionic). Synthetic polyisoprene is a clone of natural rubber. However, synthetic polyisoprenes would never reach the same level of stereospecificity as natural rubber (99% of cis-1,4-polyisoprene); therefore, some properties of the synthetic copy would not be as good as the natural source (crystalline properties), especially in terms of tear resistance, but IR remains perfectly suitable for application in gloves.
Elastomeric and Plastomeric Materials
Published in Narendra Pal Singh Chauhan, Functionalized Polymers, 2021
Mohsen Khodadadi Yazdi, Payam Zarrintaj, Saeed Manouchehri, Joshua D. Ramsey, Mohammad Reza Ganjali, Mohammad Reza Saeb
Natural rubber is usually extracted as milky and sticky fluid, known as latex, from the rubber tree, Hevea brasiliensis. The latex is rich in polyisoprene, which is currently used in many applications such as automotives, gloves, hoses and belts, balloons, balls, lining materials, and insulation. Natural rubber is one of the most consumed rubbers across the globe; nowadays, this elastomer is mainly manufactured through synthetic routes in large-scale petrochemical plants. However, synthetic isoprene rubber possesses a simple chemical structure compared to the more elaborate proteins that are abundant in nature (De and White 2001, Hanhi et al. 2007).
Dielectric Analysis of Different Natural and Synthetic Polymer Types
Published in Jose James, K.P. Pramoda, Sabu Thomas, Polymers and Multicomponent Polymeric Systems, 2019
Hugo Salazar, Pedro M. Martins, C.M. Costa, S. Lanceros-Méndez
Polyisoprene is a biopolymer based on rubber bridges (Figure 10.14). There are two types of polyisoprene: cis-polyisoprene, which is a natural rubber obtained from the tree Hevea brasiliensis, and trans-polyisoprene, produced by Pallaquium gutta. Cis-polyisoprene has good mechanical properties, like elasticity and softness. In comparison to trans-polyisoprene, it has a lower molecular weight and worse mechanical properties, as it is hard and brittle. Polyisoprene possesses properties such as high malleability at cold temperatures, high resilience, high impact and abrasion resistance, and efficient heat dispersion [74].
Personal protective equipment during COVID-19 pandemic: a narrative review on technical aspects
Published in Expert Review of Medical Devices, 2020
Sai Saran, Mohan Gurjar, Arvind Kumar Baronia, Ayush Lohiya, Afzal Azim, Banani Poddar, Namrata S. Rao
Nonpowdered gloves are preferred to powdered gloves and the use of double gloves is encouraged [16,17]. Appropriate materials for manufacturing gloves includes polyisoprene, polychloroprene, nitrile, natural rubber latex, or neoprene. The standards that need to be adhered to include the ASTM D6319-19 standard for nitrile examination gloves, ASTM D3578-19 for rubber examination gloves, and ASTM D5250-19 for polyvinyl chloride gloves. EN 374 certification on the gloves ensuring minimum level 2 protections (a glove which resists penetration to air and water, passing both air leak and water leak tests) are considered to be micro-organism resistant [57]. The updated ISO 374–5:2016 standard has introduced standards offering protection against micro-organisms, viruses in addition to fungi and bacteria, and further testing to ISO 16604 clothings for protection, against contact with blood and body fluids, is now required [16].
Kinetics of the thermal decomposition of Eucommia ulmoides Oliver leaves and its fermentation products
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Zhihong Wang, Minglong Zhang, Sheng Peng, Qiuling Yang, Mijun Peng
The pyrolysis characteristics of EULU and EULF have been investigated at different heating rates under nitrogen atmosphere. For both samples, the decomposition process could be divided into three stages, and the main weight loss was observed in the second stage. When the heating rate increased from 10, 20, 30, and 40°C, the temperature interval of each pyrolysis zone and peak temperature moved toward high temperature. Meanwhile, the KAS and FWO methods exhibited the similar kinetic characteristics for each sample, respectively. The CR method revealed the second-order model (f(α) = (1-α)2) might be the main thermal decomposition reaction mechanism of the whole pyrolysis process for both samples. However, compared to EULU, the DTG curves of EULF have changed significantly, including major pyrolysis peak, shoulder peaks, tiny peaks, and new peaks produced. At the same time, the average pyrolysis activation energy was basically close. The kinetic characteristics of pyrolysis were significantly changed through fermentation technology, which suggested that biological fermentation technology could cause main changes in chemical composition and lignocellulosic structure. It was worth noting that the pyrolysis activation energy of EUL was higher than that of common biomass plant materials. This might be closely related to the complex composition of EUL and the presence of unique gutta-percha structure (trans-polyisoprene). Therefore, the technology of microbial pretreatment and the pyrolysis model of EUL were worthy of further study.
Enhancing mechanical properties of prevulcanized natural rubber latex via hybrid radiation and peroxidation vulcanizations at various irradiation doses
Published in Radiation Effects and Defects in Solids, 2018
Sofian Ibrahim, Khairiah Badri, Chantara Thevy Ratnam, Noor Hasni M. Ali
The cis-1,4-polyisoprene polymer is the main component in natural rubber latex (NR). NR itself is a sticky and non-elastic material. The crosslinking of NR molecules via the vulcanization process makes NR heat-stable and elastic, whereby crosslinking causes changes in the physical properties of polymers. At present, there are three popular vulcanization processes being used in natural rubber latex industries; namely sulfur, radiation and peroxide vulcanizations. However, this does not mean that there is no other vulcanization process used to produce vulcanized NR latex. For example, the photo-curing of NR latex via thiol–ene reaction has also become a prominent way to cure NR lately and efforts have been made to implement it in industrial processes (1). Of all three popular vulcanization processes mentioned earlier, sulfur vulcanization produced products with superior tensile strength compared to radiation and peroxide vulcanization. However, sulfur vulcanization is able to produce by-products such as nitrosamines and nitrosatables, carcinogenic materials that may cause cancer and chemical allergies (2, 3).