Sensitive to pH advent of new thermosetting plastics
2016-01-22 admin
3745Click
Human made the good chemical stability of thermosetting plastics, but how did they become a problem recycling, such as thermosetting plastics sensitive than the decomposition temperature of its heat temperature is usually much higher. Therefore, scientists have been looking for solutions thermosetting plastics recovered problems.
Recently, researchers at the IBM Almaden Research Center put forward a new idea: to create a new type of pH-sensitive thermosetting plastic which maintains superior performance plastics, and can be broken down into small molecules monomers under acidic conditions. , thus demonstrating the reversibility.
Dr. Garcia and his team synthesized a nitrogen-containing heterocyclic polymer plastic: team synthesized under acidic conditions, nitrogen-containing heterocyclic polymer degradable plastic figure of each structure is a red and blue 135- hexahydro triazine.
Garcia et al to use a polymerizable monomer having two amino paraformaldehyde at about 50 ℃ synthesized a hemiaminal covalent network structure, and then heating is continued to 200 ℃, hemiaminal formed dehydration the 135- hexahydro triazine and forming a crosslinking point, formation of high molecular structure of plastic. Containing heterocyclic triazine just hold each other's hand and not let go, the bond good thermal stability so that this new type of thermosetting plastic has good heat resistance. The experiments show that the plastic toughness than traditional nitrogen-based polymer plastic better.
But the real point is that it break through the traditional pH sensitive reversibility of this new type of thermosetting plastic: Although it is not sensitive to temperature, but at a pH of less than 2, just after a simple decomposition reaction, a few hours after the make polymer decomposed into water and -diaminodiphenylether:
pH-sensitive plastic produced 4'4 'of decomposition - diaminodiphenyl ether which can be used to produce polyimide (PEI) and polyester resin.
Compared with the traditional reaction temperature, pH control by the benefits of this reaction is that energy consumption, easy to control the reaction. This reaction does not need to be heated to very high temperatures, does not require a long reaction chain. At the same time it kind of reaction products are also environmentally friendly - diaminodiphenyl ether can be used as raw material for synthetic plastics to be used again, not to mention the water thus ensuring the recovery of the plastic will not bring any known environmental issues .
In the invention of technological progress and at the same time, we also need to focus on the impact on the environment. This Garcia and her team invented a reversible pH-sensitive plastic is the concern of this. If the synthetic purity of this plastic can reach industrial production requirements, NA me plastic product impact on the environment is likely to be reduced. At the same time, since such thermosetting plastics having a higher toughness, its lifetime of plastic products may also be further improved, thereby indirectly reducing the plastic waste.