Biological basis of crosslinking agent

Bayer materials science and technology (BMS) recently told a news conference has developed the first biological base polyurethane crosslinking agent.
Company says it cyclopentane diisocyanate (PDI) is a new isocyanate carbon content 70%.Coatings, adhesives, special goods business executives and BMS executive committee members, Daniel, Meyer said the company recent innovations include the world's leading as coating and adhesive curing agent of PDI derivatives.
Meyer told reporters and industry experts company plans in 2015 will be the first of April PDI foundation of product release in the city, and in 2016 began to up to 20000 tons/year, enough to cover 20 million vehicles) capacity for commercial manufacturing.He said compared with the existing two-component polyurethane coating, the paint material processing rate of 30% faster.In the medium term, is likely to be suitable for mixed plastics, composite materials and the underlying metal coating.
The innovation is BMS and francois hoff institute in Germany and German machinery equipment manufacturers DURR cooperation achievements.Innovation cooperation conforms to the BMS to develop new products strategy, Meyer said: "our goal is to combine in our partner on the value chain and its technical reference as early as possible to our research and development work, to ensure that our market customer  success. In addition we will provide more and more materials and solutions."

(source:http://www.ac-chem.net/news/crosslinking-agent-91-ba85.html)

Using ratio of crosslinking agent

When using crosslinking agent, should avoid to add acid packing, also be careful when adding antioxidants and other aromatic oil additives on crosslinking effects will have bad influence, it is important to note that.About the use of the crosslinking agent ratio has eight pay attention to the point.
First, epoxy resin can be through based on acids, amines, amino resin, isocyanate, phenolic resin, such as, cold & heat curing crosslinking system;
Second, the amino resin can through based on isocyanate, carboxylic acid or anhydride, epoxy resin, phenolic resin, such as, cold & heat curing crosslinking system;
Third, can be based on acids, phenolic resin, epoxy resin and isocyanate, carries on the cold & hot crosslinking curing system;
Fourth, can be based on alkyd resin acids, amines, amino resin, isocyanate, phenolic resin, peroxide, light initiator, etc., for cold & hot crosslinking curing system;
Fifth, the acrylic resin can be based on amine, amino resin, epoxy resin, acrylic acid ester, phenolic resin, free radicals, such as for cold & hot crosslinking curing system;
Six, polyethylene can be based on peroxide, silane crosslinking, including alcohol, electron beam
Seven, regular elastomer can be based on sulphur, peroxide, acrylic acid ester, etc, for cold & hot crosslinking curing system;
Eight, special elastomer can be based on a metal oxide, silicon alkoxide, resin, amine, cold & hot crosslinking curing system.

(source:http://www.ac-chem.net/news/crosslinking-agent-22-b1da.html)

The nature of crosslinking agent

Crosslinking agent is a kind of can plays a role of bridge between the linear molecule, allowing multiple linear molecules mutual couplet net structure of bonding material.Promote or adjustment between polymer molecular chain covalent bond or electrovalent bond formation of the material.Crosslinking agent in different industries have different name, such as: used in rubber industry is called "vulcanizing agent";In the plastic industry known as "curing agent, curing agent, curing agent;In adhesive and coating industry known as "agent" and "curing agent", etc.Despite the difference in the above address, but reflects the chemical properties and mechanism of are the same.
Often is material containing multiple functional groups in the molecule, such as organic dibasic acid, polyol, etc;Compounds or molecules contains more unsaturated double bond, such as divinylbenzene and diisocyanate, N, N - methylene double acrylamide (MBA), etc.But with monomer feeding, polycondensation (or aggregate) to a certain degree of crosslinking, make the product into insoluble cross-linked polymer;Also can keep a certain number of functional groups in linear molecules (or double bond) and then add certain substances to crosslinking, such as the curing of phenolic resin and rubber vulcanization, etc.

(source:http://www.ac-chem.net/news/crosslinking-agent-28-832c.html)

Mechanism of coupling agent

Since the 1960s, scientists study the mechanism of coupling agent. Has made great progress, although not yet a consensus, but explained by chemical bond theory has been confirmed by a large number of experiments. R-Si-OR the type of coupling agent of different end group can react with polymers and fiber respectively to bond.By connecting two phase of the chemical bonds of interfacial bonding to improve.Tesla's research shows that deposition on the surface of the glass fiber, coupling agent usually contains components of physical and chemical adsorption of non-uniform layers, rinse with cold water to wash it by hydrogen bonding connection part of the coupling agent, wash with hot water can wash away with silica and the key connection body, at the end of the molecular layer, fiber with multiple key silica and silane coupling agent combined with very strong, it plays a main role to improve the interface bonding strength, and physical adsorption of the components is ineffective or even harmful.So the concentration of the coupling agent on the interface bonding can also have an impact, such as glass fiber in different concentrations of KH550 (gamma - ammonia propyl triethoxy silane) soaked in the solution after 10 min made sample, test results show that the coupling agent content was 0.4% ~ 0.4% (mass fraction) within the scope of the effect is best, in 8% of high content in the solution treatment effect is the worst.When coupling agent concentration is too low, the glass fiber on the adsorption capacity is insufficient, the concentration is too high adsorption in silane is arranged on the surface of the fiber mixed and disorderly, the corresponding physical adsorption layer thickening, unfavorable to interface bonding.

(source:http://www.ac-chem.net/news/mechanism-of-coupling-agent-8168.html)

Biological molecules crosslinking theory significance

The natural crosslinking of biological molecules is a kind of natural movement, it with other material movement with the same side.In nature, all kinds of inorganic always exists in the form of relatively stable, the stable forms like celestial body movement, is to follow certain laws of nature after a long interaction and evolution into some sort of balance and stability of a state.In this state and universality of phenomenon shows that various substances have themselves and the environment balance and stability of a kind of trend, biological molecules of natural crosslinking is a reflection of this trend in organic biology.Each organism is a complex chemical system, system of various biological molecules contain a large number of chemically active groups, is a kind of unstable factors, they must interact with chemical balance and stability, and this makes between itself and the molecular biological molecules progressive natural crosslinking, this natural crosslinking is biological molecules tend to chemical equilibrium and stability of a natural change, is a form of physical exercise, in the process of the movement, the biological activities of various kinds of biological molecules is also accompanied by a gradual change between the molecules and molecular structure change, so as to show the cell differentiation, biological aging phenomenon and law and a series of phenotypic change.Molecular cross-linking is one of the important chemical nature in the process of life change, its nature synergy with other involved in the whole process of life, form a complete system of life science.According to this principle, drugs could be developed and design experiments to explore life senescence as well as the basic method for prevention and treatment of some diseases.While under the condition of existing in molecular crosslinking methods to artificially change the sequence of gene inactivation to reshape the creature also is very difficult, but with a certain method to alter the biological phenotype and prevention, treatment of certain diseases or predictable;Although under physiological capacity in the existing scientific level limit of biological molecules cross-linked to a certain degree is impossible, but with slow natural crosslinking to slow the speed of aging is feasible and promising;Laboratory diagnosis, we can detect the molecular biological tissue crosslinking degree to calculate the biological age of biological tissue.Therefore, we think it is necessary to study on this subject use of advanced technology, the necessary scientific experiments, in order to establish a complete earlier theoretical system to make it to the direction of more accurate and more complete and eventually service to humans.

(source:http://www.ac-chem.net/news/biological-molecules-crosslinking-theory-significance-91aa.html)