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Background
Published in Jie Zhang, Chuanjun Han, Rubber Structures in Oil and Gas Equipment, 2022
Rubber can be divided into natural rubber and synthetic rubber (Figure 1-1). Natural rubber is formed by coagulation, washing, molding, and drying of the sap collected directly from rubber trees. However, with the development of science and technology, natural rubber gradually cannot meet the complex requirements of civilization. Humans have begun to seek rubber with more superior performance. Thus, synthetic rubbers synthesized from various monomer materials have begun to be developed.
The Rejection of Perfection
Published in Sharon Ann Holgate, Understanding Solid State Physics, 2021
While synthetic rubber is manufactured from petroleum, natural rubber is the latex of the rubber tree (Hevea brasiliensis) from South America. Although it can be used in its natural state, rubber can be made much more elastic and less sticky by adding sulphur to it. The process of adding sulphur to rubber is known as vulcanisation and was invented by Charles Goodyear in 1839. Some of the sulphur atoms form cross-links between chains, which then make the rubber harder. If more and more sulphur is added, rubber eventually becomes a hard solid known as ebonite.
End-of-Arm Sensors
Published in David D. Ardayfio, Fundamentals of Robotics, 2020
Natural rubber provides the best mechanical properties but is susceptible to environmental degradation. Silicone rubber provides compatible performance at some sacrifice in hysteresis. Neoprene is environmentally robust and is the elastomer of choice for all but the softest units.
Energy absorption capacity of rubber sponge reinforcement in carbon fiber reinforced plastics (CFRP) tubes
Published in International Journal of Crashworthiness, 2023
Kunanon Sakkampang, Nirut Onsalung
Thailand is the largest producer of natural rubber (NR) for domestic use and is also the world's largest producer of natural rubber [28]. Natural rubber is an important renewable polymer material with high flexibility and excellent mechanical properties. It can be easily produced into high porosity NR foam, with low density and strong hydrophobic properties [29–31] making it a very suitable material for impact resistance. Most of the time, latex is used to make rubber sponge by the Dunlop method or Talalay process to get a pillow-like sponge. Although Talalay process offers foam with better flexibility and physical properties than Dunlop, Dunlop process is mainly used in Thailand due to its low production cost [32]. Sponges obtained from the Dunlop or Talalay process are used to make weight-bearing materials such as pillows [33], latex mattresses [34], heel pads, etc. due to its high flexibility and ability to absorb good weight even though the sponge is lightweight. In addition, its flammability from combustion is similar to that of normal materials [35]. Therefore, it is suitable to be used as a cushioning material inside the bumper of a car that may have collision or a fire extinguisher. With good mechanical properties, therefore, the researchers aim to study about the application of Thai latex to increase the value of Thai latex which its price is very low. In this study, the focus will be on the use of rubber sponges to absorb shock inside the front parts of a car by reinforcing it with carbon fiber material to aid in better impact resistance.
Natural rubber latex-modified asphalts for pavement application: effects of phosphoric acid and sulphur addition
Published in Road Materials and Pavement Design, 2019
Wachira Saowapark, Chanchira Jubsilp, Sarawut Rimdusit
Natural rubber (NR) is a renewable and ecologically friendly elastomer. It also possesses good elasticity and outstanding properties under cyclical loads. It is more cost-effective compared to synthetic polymer modifiers for asphalts, particularly in Thailand, one of the leading producers of NR in the world. For less severe mixing condition, NR in latex form can be used as an asphalt modifier because natural rubber latex is ready to disperse in liquid asphalt at the temperature of 150°C or lower, utilising relatively low mixing speed of 500 rpm, and mixing time of ca. 30 min compared to the mixing condition of crumb rubber-modified asphalt, i.e. 180°C and mixing speed of 7000 rpm for 1 h (Xiang et al., 2009) or SBS-modified asphalt, i.e. 180°C, mixing time of 40 min at a mixing speed of 4000 rpm followed by 2 h mixing using a mechanical stirrer (Zhang & Hu, 2013). In 2013, the Department of Highways, Ministry of Transport of Thailand has issued a specification of NR-modified asphalt cement for road surfaces as well as maintenance of existing road surfaces in order to promote the utilisation of this major agricultural product of Thailand (Department of Highways Ministry of Transport Thailand, 2013). That announcement provided a general guideline to the researchers to develop various NR-modified asphalt formulations to suit various types of road pavement conditions in Thailand (Read & Whiteoak, 2003; Vichitcholchai, Panmai, & Na-Ranong, 2012).
Mathematical modeling of drying kinetics and property investigation of natural crepe rubber sheets dried with infrared radiation and hot air
Published in Drying Technology, 2018
Yutthapong Pianroj, Warit Werapun, Jutharat Inthapan, Saysunee Jumrat, Seppo Karrila
Southeast Asia or ASEAN is the main tropical region suited for cultivation of rubber trees (Hevea brasiliensis). They are grown mainly in three countries within this region: Indonesia, Thailand, and Malaysia. The total growing area in these three countries represents about 60% of the rubber cultivation area globally. Therefore, natural rubber products are important to these regional economies. Thailand in year 2015 produced 4.47 million-tons of natural rubber products that ranked sixth among the products exported from Thailand.[1] These natural rubber (intermediate) products are raw materials used in many industry sectors, in applications such as automotive tires, seals, couplings, footwear, molded products, gloves, medical devices, etc. The intermediate products are usually in the form of ribbed smoked sheets or concentrated rubber latex. However, an emerging trend in Thailand is to produce natural crepe rubber sheets (NCRS) because these are easy to produce and require less investment than the above-mentioned conventional forms. The NCRS is made from natural cup lump rubber milled in a crepe machine to small pieces, then pressed into sheets and cleaned with water to remove contamination. The NCRS obtained has high moisture content. Normally, the moisture content is reduced by drying the NCRS in open air for around 1 month, to get the moisture content to about 7% or less.