一. 课文 What are polymers? For one thing, they are complex and giant molecules and are different from low molecular weight compounds like, say, common salt. To contrast the difference, the molecular weight of common salt is only 58.5, while that of a polymer can be as high as several h...
Synthetic Polymers, commonly known as plastics, have been entering the marine environment in quantities paralleling their level of production over the last half century (Thompson). However, during the last decade of the 20Century, the deposition rate accelerated exponentially (Copello, Ogi). Thirty ...
The term polymer is often used to describe plastics, which are synthetic polymers. However, natural polymers also exist; rubber and wood, for example, are natural polymers that consist of a simple hydrocarbon, isoprene, according toEncyclopedia Britannica. Proteins are natural polymers made up of a...
Polyamines are organic chemical compounds with molecules composed of at least two amino groups. Many types of polyamines are produced naturally in living organisms, including humans, and are involved in some biological processes. Synthetic polyamines also exist and are produced for industrial use. These...
Chlorinated hydrocarbons are actually used as stabilizing agents themselves. They are used on PVC pipe to keep it chemically stable. They're so stable that it's been hard to come up with good ways to get rid of them! They linger in the environment and even though some is naturally produced...
根据第三段中的“The advantage of synthetic polymers lies largely in their excellent stability and various mechanical qualities.However,due to their high durability,waste materials made of these polymers have accumulated in the land and oceans,causing serious concerns for the ecosystem.”可推知,该段...
Polymerization is the process of creating synthetic polymers by combining smallmonomermolecules into chains held together by covalent bonds. The two major forms of polymerization are step-growth polymerization and chain-growth polymerization. The main difference between them is that in chain growth polymer...
HDPE bottles are sturdier than LDPE ones. 12 Polyester Any of numerous synthetic polymers produced chiefly by reaction of dicarboxylic acids with dihydric alcohols and used primarily as light, strong, weather-resistant resins in boat hulls, textile fibers, adhesives, and molded parts. 3 Polyethylene...
Examples of elastomers are natural rubber or synthetic rubber such as EPDM and NBR. Basically, thermoplastic elastomers can be divided into two types: reactor-made TPEs (e.g. TPA, TPU, and TPC) and TPE compounds (e.g. TPS or TPV). The properties of reactor-made TPEs are implemented in...
surface area, silica fumes promote adhesion through nano-sized primary particles, and attapulgite is an exceptionally effective gellant. Polymeric modifiers like acrylate polymers and polyamide wax exhibit stable viscosity over a wide pH range and are applicable in most solvent-based synthetic resin ...