Why polystyrene dissolves in acetone
Xylenes are found in coke gases, in gases obtained in the dry distillation of wood (hence their name: xylon means wood in Greek) and in some oils. They have very good combustion behavior in a gasoline engine and for this reason attempts are made to increase their content in catalytic reforming processes.
Xylenes are harmful. Their vapors can cause headaches, nausea and general discomfort. Like benzene, it is a narcotic agent. Prolonged exposure to this product may cause alterations in the central nervous system and hematopoietic organs.
Those hydrocarbons that result from substituting two hydrogen atoms of benzene for two molecules of the methyl radical, belonging to the second series of benzene isomers, like all substitution derivatives of benzene, can exist under the isomeric modifications ortho, meta and para:
Solubility of polypropylene
Any analysis of a plastic begins with preliminary tests. In addition to observing characteristics such as solubility, density, softening and melting behavior, heating in a combustion tube (pyrolysis test) and in a flame (flame test) is very important.
Due to the high molecular weight of the polymers it is necessary to chop the sample as finely as possible. If the sample is difficult to cut, it can be frozen with carbonic snow or liquid nitrogen, which will make it glassy, more brittle and easier to cut.
Among the numerous plastic solvents, the most widely used are benzene, tetrahydrofuran, dimethylformamide, diethyl ether, acetone and formic acid. In certain cases, chloroethylene, ethyl acetate, ethanol, methanol, toluene, hydrocarbons and even acids or bases are often used.
Nylon has a high breaking strength, high elasticity and low density. It melts at temperatures of around 260 ºC and softens at 180 ºC. By condensation polymerization, a filamentous, whitish paste is obtained, which becomes elastic and resistant when cooled. It burns smoothly and melts. It is quite stable against chemical agents.
Both compounds are polymers, i.e. long chains formed by the repetition of a unit molecule or monomer. From a chemical composition point of view, the difference is that polyethylene is a polymer of ethylene (two carbon and four hydrogen atoms) (CH2-CH2)n; while polypropylene is a polymer of propylene (three carbon and six hydrogen atoms) (CH2- CH2-CH2-CH2)n.
Polyethylene is the most widely used plastic in the world and is used to manufacture most of the plastic products that surround us (shopping bags, detergent containers, gel, cleaning products, etc.).
One of the most frequent uses of polyethylene in our daily lives is in plastic bags. Compared to polypropylene, polyethylene is more resistant to low temperatures, is easier to stretch, has greater flexibility and resistance to wear, abrasion and impact. It is also a cheaper product than polypropylene.
For example, the linear polyethylene of very high density and high molecular weight, HMW-HDPE (high density polyethylene) is used for the manufacture of parts for industrial machinery that require high strength, while branched polyethylene or very low density and low molecular weight, LMW-VLDPE (very low density polyethylene) is used, among other applications, as plastic film.
How to dissolve plastic
Sometimes some of the carbons, instead of having hydrogens attached to them, have long polyethylene chains associated with them. This is called branched polyethylene, or low density polyethylene, or LDPE. When there is no branching, it is called linear polyethylene, or HDPE. Linear polyethylene is much stronger than branched polyethylene, but branched polyethylene is cheaper and easier to manufacture.
Polyethylene was first synthesized by German chemist Hans von Pechmann who prepared it by accident in 1898 while heating diazomethane. When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the waxy white substance he had created, they recognized that it contained long chains of methylenes (-CH2-) and labeled it polymethylene.
Polyethylene is a thermoplastic polymer consisting of long hydrocarbon chains. Depending on the crystallinity and molecular weight, a melting point and glass transition may or may not be observable. The temperature at which this occurs varies strongly with the type of polyethylene. For common commercial grades of medium and high density polyethylene, the melting point is typically in the range of 120 to 130°C (248 to 266°F). The average melting point of commercial low density polyethylene is typically 105 to 115°C (221 to 239°F).