Chain transfer agent

Chain Transfer Agent

I. Introduction to Chain Transfer Agents

Chain transfer agents (also known as molecular weight regulators) are substances that control the molecular weight of polymers and reduce polymer chain branching. They are characterized by a high chain transfer constant, meaning that even a small amount can effectively reduce the molecular weight of the polymer, resulting in a low molecular weight, narrow and uniform molecular weight distribution, and stable product quality. Chain transfer agents are highly reactive substances that readily undergo chain transfer reactions with free radicals, terminating the active chain while the regulator molecule itself forms a new free radical. This new radical still possesses initiating activity, so adding a regulator can reduce the polymer molecular weight without affecting the polymerization rate.

II. Reaction Mechanism of Chain Transfer Agents

Chain transfer agents, also known as molecular weight regulators, can be illustrated using free radical polymerization as an example. The chain transfer reaction can be represented as follows:

Mx· + YS ——> MxY + S·

WhereYS is the chain transfer agent,Mx· is the chain free radical. In this process, the free radical transfers from the long chain toS, andS· can initiate a new active chain. The overall effect is to shorten the chain and reduce molecular weight. Compounds used as chain transfer agents have relatively large chain transfer constants.

III. Advantages and Disadvantages of Conventional Chain Transfer Agents

Chain transfer agents can be attacked by long-chain free radicals to abstract atoms or groups, converting the long-chain free radical into a dead macromolecule and regenerating a free radical with initiating and propagating activity. Therefore, a good chain transfer agent only reduces the degree of polymerization or molecular weight without affecting the polymerization rate. Its dosage can be calculated using the average degree of polymerization equation, but kinetic parameters for free radical polymerization are difficult to find, and even the chain transfer constant of the same regulator varies with polymerization conditions. Thus, the dosage can only be determined through multiple experiments. Traditionally, thiol compounds have been used, such as n-dodecyl mercaptan, sec-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol, mercaptoacetic acid,IOMP, etc.

Although thiol compounds have high chain transfer efficiency, they all contain sulfur, have a distinctive foul odor, are difficult to volatilize, pollute the environment, and are toxic. Moreover, they are hazardous chemicals requiring special handling during transportation, storage, and use, which is not only troublesome but also costly. Their residues affect sensory evaluation, so for environmental reasons, more and more free radical polymerizations are switching to environmentally friendly, odorless chain transfer agents.

IV. Wuxi Zhiyuan Chemical Co., Ltd. Specializes in Supplying Odorless Chain Transfer AgentAMSD

The most commonly used odorless chain transfer agent currently isα-methylstyrene dimerAMSD, with the chemical composition:2,4-diphenyl-4-methyl-1-pentene. Particularly, the Japanese importedα-methylstyrene dimerAMSD offers advantages such as high content, stable quality, no odor, andFDA certification. It is a truly odorless chain transfer agent and has been widely used in various acrylic resins. In the production of acrylic resins and acrylate polymers, addingAMSD can effectively regulate the molecular weight of acrylic resins, resulting in low molecular weight, uniform molecular weight distribution, good leveling, consistent viscosity, bright appearance, good transparency, and excellent weather resistance.

Chain transfer agentAMSD is sulfur-free, odorless, safe, and environmentally friendly, withFDA certification. It is widely used in various acrylic resins, styrene,ABS,ACR,MBS,PS,EPS, styrene-acrylic latex, latex, styrene-butadiene latex, and other polymerization reactions. It is a truly environmentally friendly, green molecular weight regulator, chain transfer agent, chain terminator, and polymer modifier. The product has the following applications:

1.In the production of acrylic resins and acrylate polymers, adding chain transfer agentAMSD can effectively regulate the resin molecular weight, resulting in low molecular weight, uniform molecular weight distribution, good leveling, consistent viscosity, bright appearance, good transparency, and excellent weather resistance.

2.In the production of latex, styrene-butadiene latex, styrene-acrylic latex, and other polymers, adding chain transfer agentAMSD results in finished resin with low molecular weight, uniform molecular weight distribution, good leveling, and consistent viscosity, allowing the product to complete polymerization according to process requirements.

3.In the production of processing aidACR, it can effectively control the intrinsic viscosity of the product.

4.High-impact polystyrene andABS resins, provide good crack resistance and low-temperature performance.

5. SAN resins, vinyl polymers (vinyl polymers), control molecular weight and uniformity.

6. EVA polymers, reduce fish-eye formation and haze.

7. EPS, resulting in polymer particles with narrow particle size distribution and good surface properties; when used in combination withPE wax, it enables recycling ofEPS.

8.Rubber-modified styrene resins, resulting in good melt flow and odorless products.

9.Vinyl polymers (vinyl polymers), in suspension polymerization reactions.

10. PE cross-linked products, used as a scorch inhibitor.

V. Advantages of Chain Transfer AgentAMSD

The Japanese imported odorless chain transfer agentAMSD is a truly environmentally friendly, green molecular weight regulator with the following advantages:

1.Light color:APHA color number around5, appearing as a colorless transparent liquid.

2.Low odor: Odor is much lower than other chain transfer agents, replacing sulfur-containing and other odorous products.

3.Regulation efficiency:

①In the production of acrylic resins,ACR, and acrylate polymers, adding this product can effectively regulate resin molecular weight, resulting in low molecular weight, uniform molecular weight distribution, good leveling, consistent viscosity, bright appearance, and good transparency;

②In the production of latex, styrene-butadiene latex, styrene-acrylic latex, and other polymers, adding this product can effectively control the molecular weight of the finished product, ensuring uniform molecular weight distribution, allowing the product to complete polymerization according to process requirements, with good leveling and consistent viscosity.

4.Safe and environmentally friendly: This product isFDA certified, making storage and use safer and more convenient.

5.Higher cost-effectiveness: Improves product quality (surface, weather resistance, odor, transparency, etc.) and reduces overall costs.

6.Higher stability: The chain transfer agent maintains consistent quality during long-term storage without changes over time.

Wuxi Zhiyuan Chemical Co., Ltd. maintains year-round stock in Wuxi and offers free samples and technical services. Welcome to inquire, thank you.

Wuxi Zhiyuan Chemical Co., Ltd.

Tel: 0510-8282 0023;

Contact:Pu Wenquan13506173961 (also WeChat ID);

Qin Haibin13915293460 (also WeChat ID).