China
Africa
Explore chapters and articles related to this topic
Mechanism, Anti-Corrosion Protection and Components of Anti-Corrosion Polymer Coatings
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Polymer Coatings, 2020
Akarsh Verma, Naman Jain, Shweta Rastogi, Vaishally Dogra, Sanjay Mavinkere Sanjay, Suchart Siengchin, Rokbi Mansour
Acrylic: Good photostability, high adhesion and film forming properties of acrylic copolymer and polymer increase their application in coating industry. The main reason of growing interest of acrylic is high resistance to ultraviolet radiation, hydrolysis, environment stability and chemical inertness [59]. But they have poor performance in acid rain due to hydrolysis and is replaced by modified acrylics such as silane-modified acrylics, epoxy acid acrylics and carbamates. Higher durability, adhesion and quick drying are the major advantages of acrylic solvent-borne coating as compared to waterborne coating. Solvent evaporation mechanism takes place when hardening of coating film occurs. The most commonly used cross-linking agents are isocyanates and amino resin, whereas identical curing process occurs for water- and solvent-borne coating which may be accelerated by catalyst (tertiary amines and organometallic compounds). The advantage of waterborne coating over solvent-borne coating is low VOC emission.
Plastics
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Acrylic or polymethyl methacrylate (PMMA) is available in a wide variety of translucent or transparent, clear or brightly coloured sheets. It softens at 90°C and burns rapidly with falling droplets of burning material. Stress crazing may occur where acrylic has been shaped in manufacture and not fully annealed, but generally the material is resistant to degradation by ultraviolet light. Acrylic is frequently used for decorative signs, rooflights and light fittings. Baths and shower trays are manufactured from acrylic as a lighter alternative to cast iron and ceramics. Although not resistant to abrasion, scratches can usually be polished out with proprietary metal polish. Polymethyl methacrylate from industrial and commercial sources can be fully recycled when clean and separated from other waste materials.
Nanogenerators as a Sustainable Power Source
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Nanogenerators, 2023
Muhammad Mudassir Iqbal, Gulzar Muhammad, Tania Saif, Muhammad Shahbaz Aslam, Muhammad Arshad Raza, Muhammad Ajaz Hussain, Muhammad Tahir Haseeb
Recently, based on triboelectricity, a new kind of generator has been invented that utilizes conventional organic materials, thus making it cost-effective, light, and easy to scale up and fabricate (Wang 2013). The energy conversion efficiency obtained through the TENG is 55% (Lin et al. 2015). TENG has arch-shaped upper and lower plates made up of PET with multilayer core, bent naturally by heat treatment as shown in Figure 12.2(a), which helps to effectively separate charge and contact with help of film elasticity. The fabrication of the unit is shown in Figure 12.2(b). Forming an upper and a lower layer of the functional core, holding a sandwiched structure, is a polytetrafluoroethylene (PTFE) film having copper deposition as back electrodes. An exposed PTFE surface was used to create PTFE nanowire arrays through a top-down method by reactive ion etching, which helps to increase the charge density of contact esterification (Fang et al. 2009; Yang et al. 2013). Figure 12.2(c) reveals scanning electron microscopy results in the form of image-aligned PTFE nanowires, indicating that the average length of PTFE nanowire is 1.5 ± 0.5 µm and the average clustering diameter is 54 ± 3 nm. Functional core with top and bottom layers has a thin film of aluminum with a nanoporous surface, sandwiched between layers as shown in Figure 12.2(d), works as both contact surface and electrode. The depth and average diameter of aluminum nanopores are 0.8 ± 0.2 µm and 57 ± 5 nm, respectively, having a distribution density of 213 µm−2. Acrylic, on account of its lightweight, low cost, decent strength, and good machinability was chosen as structural supporting material (Chen et al. 2015).
The evolutionary process and damage characteristics to the target of jet flame produced by the Al/PTFE mixed powder in a small caliber projectile with through-hole
Published in Waves in Random and Complex Media, 2022
Enling Tang, Zhen Zhang, Ruizhi Wang, Yafei Han, Mingyang Xu, Chuang Chen, Mengzhou Chang, Kai Guo, Liping He, Wenhao Yu
According to Table 5, when the shock wave overpressure reaches 100 kPa, it can cause significant damage. In the static explosion experiment in confined space, the overpressure peaks of the jet flame are 505,000, 632,000, 927,000, 1,353,000, and 1,890,000 kPa, respectively. Due to the dilute effect of flame overpressure and high temperature, the acrylic near the projectile nozzle softens and decomposes. Due to the small size of the projectile in this paper, the flame can only cause obvious damage to the local area in the closed environment and the action time is short, resulting in a poor damage effect. As an engineering plastic material, acrylic has the characteristics of high light transmittance and high chemical stability. Its melting and decomposition temperatures are 180 and 350°C, respectively. During the experiment, the electric igniter in the projectile detonated Al/PTFE mixed powder and produced high-temperature and high-pressure flame in the confined space. The conical hole wall and cylindrical hole wall of the acrylic block soften and deform or even decompose under high temperature and high pressure, resulting in the expansion of the cylindrical hole with a diameter of 20 mm at the left end of the acrylic block and the formation of pits near the bullet through-hole on the conical hole at the right end. Figure 16 shows the morphology of acrylic blocks before and after the static initiation experiment in the confined space.
Polyacrylate/silica hybrid materials: A step towards multifunctional properties
Published in Journal of Dispersion Science and Technology, 2019
However, only a few reports have focused in detail on the acrylic polymers which have gained enormous attention recently. This review paper talks exclusively about this fascinating class of polymers. The term “acrylic” refers to those polymers that contain acrylate or methacrylate esters in their structure along with other vinyl unsaturated compounds.[15] These are widely used in coatings, adhesives, and textiles due to their strength, clarity, film-forming properties, transparency, gloss and their resistance to photo-degradation.[16] The properties of acrylates can be tailored by producing copolymers to obtain desirable properties. The most common co-monomer used is styrene which being aromatic imparts several properties such as strength, hardness, hydrophobicity and is relatively inexpensive. Thus, acrylic latexes are widely classified as styrene-containing and non-styrene latexes. Acrylic polymers have found applications in various areas but there are certain limitations to their use which cannot be overlooked. Poor water resistance and temperature dependence limit its use as external coatings. These limitations can be overcome by use of hybrid materials in which inorganic particles are incorporated into the organic phase such that there is an interaction between the two phases at the molecular level. The incorporation of inorganic phase imparts multifunctional properties to the system and thus provides scope for overcoming the limitations of each phase individually.