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Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
Polysulfide polymers can be prepared from various organic or inorganic sulfur compounds, such as alkali metal sulfide or polysulfide, S8, sulfur chloride, cyclic sulfides, dithiols, and sulfur dioxide (SO2). First methods for the preparation of polysulfide polymers from organic or inorganic sulfur compounds other than SO2 are briefly described. Finally polysulfide polymers prepared from SO2 are described.
Sealants, gaskets and adhesives
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Polysulphide sealants are available as one- or two-component systems. The one-component systems have the advantage that they are ready for immediate use. They cure relatively slowly by absorption of moisture from the atmosphere, initially forming a skin and fully curing within two to five weeks. One-component systems are limited in their application to joints up to 25 mm in width, but their ultimate performance is comparable to that of the two-component materials. Typical uses include structural movement joints in masonry, joints between precast concrete or stone cladding panels, and sealing around windows. The two-component polysulphide sealants require mixing immediately before use and fully cure within 24–48 hours. They are more suitable than one-component systems for sealing joints that are wider than 25 mm, have large movements, or are subject to vandalism during setting. Uses include sealing joints within concrete and brickwork cladding systems and also within poorly insulated lightweight cladding panels. Polysulphides have a life expectancy of 20–25 years. (The typical movement accommodation for polysulphide sealants is up to 25% for one-part systems and up to 30% for two-part systems.)
Preparation and mechanical properties of poly (urea–formaldehyde) microcapsules containing liquid polysulfide
Published in The Journal of Adhesion, 2021
Xuan Wang, Xianlian Mu, Haowei Wang, Shengzhi Liao, Huaiyu Yang
Polysulfide sealants are a two-part elastic sealing material consisting of mercapto-terminal liquid polysulfide as a main agent and metal oxide as a curing agent, which can be vulcanized by chemical crosslinking at room temperature or heating. They are extensively used in various industry fields due to their low water-vapor transmission, excellent durability, flexibility, adhesive properties, and long-term resistance to solvents and sunlight. Particularly in modern aircraft, polysulfide sealants play an important role in the sealing and anticorrosion of integral fuel tanks, cabins, windshields, fuselages, and wing structures.[1–3] However, taking a wide view of relevant reports at home and abroad, the application of polysulfide sealants in the assembling process of aircraft is still in a traditional method, which generally includes proportioning, mixing, dipping, assembling, and surface removing.[4] Obviously, this traditional method based on the manual operation not only consumes a lot of time and labor costs but also has a low working efficiency, and even uncoated or less-coated events sometimes happen, consequently resulting in the unstable and unreliable of assembling quality.[5]
Application of butane-1,4-diyl bis(2-mercaptoacetate) as dithiol prepolymer for preparation of polythiourethane and clay-based nanocomposites
Published in Journal of Sulfur Chemistry, 2022
Amin Pirayesh, Nazanin Qolizade, Saeid Talebi, Mehdi Salami-Kalajahi
Nowadays, polymer rubbers have marvelous applications such as in military [1], medical [2], airplanes [3], and automotive [4] industries. Polysulfides are one of the most prominent rubbers with excellent properties such as solvent and oil resistance, resistance against abrasion and wear, self-healing properties, resistance to ultraviolet irradiations and ozone, and so on [5–8]. The sulfur atom has an important role in the polymer chains and this parameter influences chemical and physical properties, especially hydrophobicity and glass transition [5].
Poly(ethylene disulfide)/carbon fiber composites: cure and effect of fiber content on mechanical and thermal properties
Published in Journal of Sulfur Chemistry, 2021
Milad Sheydaei, Milad Edraki, Ebrahim Alinia-Ahandani, Erfan Nezhadghaffar-Borhani
Polysulfides and their derivatives are suitable candidates for a variety of coatings, adhesives, sealants, and insulators cause of their high resistance to common chemicals and low permeability to gases and organic liquids [1–5]. Polysulfide polymers are usually produced by the reaction between alkyl chlorides and sodium polysulfides [6]. This polymer harmonizes with epoxy, acidic, and hydroxyl groups [7,8]. In recent years, the use of polysulfides has many applications in various fields, such as bipolar plates for fuel cells, solar cells, lithium batteries, cell-penetrating, and gene delivery [9–16]. Interfacial polymerization has been reported as a powerful method for the synthesis of polysulfide polymers [17]. Also, this method was used for producing fibers, capsules, and ultrathin films [18]. As mentioned, these polymers have suitable chemical resistance, but their mechanical properties are partly weak and these properties can be improved with various fibers such as Kevlar, carbon fiber (CF), glass fiber, and natural fibers [19–24]. The CF has acceptable properties that include high strength, modulus, and nice electrical conductivity properties. Also, it will be used for the special technologies such as aerospace and sensors [25–31]. Among the different methods for the preparation of polymer nanocomposites; in situ polymerization method is an efficient technique. Excellent dispersion and distribution of the filler in the matrix can be achieved by using this method [32,33]. In addition, dispersion and distribution can be improved by modifying the nanoparticle surface and functional groups or use of basic strategies such as ‘grafting to’, ‘grafting from', and ‘grafting through' to graft the polymers onto the surface of nanoparticles [34–44]. Cross-linked structures in several vulcanizations are shared in the sulfur systems and elastomers that include radical initiation, UV irradiation, and initiated metal oxide [45–47]. Mahon and coworkers have considered curing of polysulfide with MnO2 and NaBO3 via thermal and photo degradation and detected two ways that are free radical autoxidation technique and (ii) hydrolysis [48]. Li and coworkers have studied on the influence of the concentration of graphene oxide on the mechanical properties of polysulfide rubber. At first, they have functionalized graphene oxide with liquid sulfur and then, discussed on the elongation at break and tensile composite [49].