What is the reason for the unstable heating of PVC?

Answer: ① The molecular chain structure contains initiator residues containing allyl chloride to act as an activating group. The terminal double bond reduces the thermal stability; ② the effect of oxygen accelerates the dehydrogenation of PVC during thermal degradation; ③ The HCl produced by the reaction has a catalytic effect on the degradation of PVC; ④ The effect of the amount of plasticizer.

What is a polymer material processing aid and what does it do?

Answer: Auxiliaries are various auxiliary chemicals that need to be added during the production or processing of certain materials and products to improve the production process and product performance. Resins and raw rubber are processed into plastics and rubber products. Various auxiliary chemicals needed.

Role: ①Improve the technological performance of polymers, optimize processing conditions, and submit processing efficiency; ②Improve the performance of products, increase their use value and life.

The property refers to the performance that additives and polymers can be uniformly and mixed together for a long time without producing phase separation and precipitation.

What does a plasticizer do?

Answer: Weaken the Van der Waals force of the secondary valence bonds between the polymer molecules, thereby increasing the mobility of the polymer molecular chains and reducing the crystallinity of the polymer molecular chains.

What are the main functions of heat stabilizers?

Answer: ① Absorb and neutralize HCL and inhibit its autocatalytic effect; ② Replace the unstable allyl chloride atom in the PVC molecule and inhibit the release of HCl; ③ Addition reaction with the polyene structure and destroy the formation of large conjugated system , Reduce coloration; ④ capture free radicals and prevent oxidation reactions; ⑤ neutralize or passivate metal ions or other harmful substances that play a catalytic role in degradation; ⑥ protect, shield and weaken ultraviolet radiation.

Why is UV the most destructive to polymers?

Answer: The ultraviolet wavelength is short and the energy is large, which interrupts most polymer chemical bonds.

Why is plastic easily susceptible to static electricity during processing or use?

Answer: Since the molecular chains of the host polymer are almost all covalently bonded, they cannot ionize or transfer electrons. During its processing and use of products, when it wants to contact and rub with other objects or itself, it will be charged due to the gain and loss of electrons, and it will be difficult to disappear by its own conduction.

What is the definition of lubricant and the difference between internal and external lubricants?

Answer: Lubricant-can improve the friction and adhesion between the particles of plastic layers and the melt and the metal surface of the processing equipment, increase the fluidity of the resin, and can adjust the plasticizing time of the resin to maintain continuous production. Agent, which is called lubricant.

The external lubricant can increase the lubricity of the plastic surface during processing, reduce the adhesion between the plastic and the metal surface, and minimize the mechanical shear force, so as to achieve the easiest processing and molding without damaging the performance of the plastic. purpose. The internal lubricant can reduce the internal friction of the polymer, increase the melting rate and melt deformability of the plastic, reduce the melt viscosity and improve the plasticization performance.

The difference between internal and external lubricants: internal lubricants require better compatibility with polymers, reduce friction between molecular chains, and improve flow properties; while external lubricants require certain compatibility with polymers to reduce polymers Friction with processing machinery surfaces.

What factors affect the strength of reinforced plastics?

Answer: ① The strength of the reinforcing agent is selected to meet the requirements; ② The strength of the basic polymer can be satisfied by the selection and modification of the polymer; ③ The surface cementation of the plasticizer and the basic polymer; ④ The structure of the reinforcing material material.

What is a masterbatch?

Answer: It is an aggregate made by uniformly loading super constant pigments or dyes into the resin; basic composition: pigments or dyes, carriers, dispersants, additives; Role: ① It is beneficial to maintain the chemical stability of pigments And the stability of color; ② make the pigment have better dispersibility in plastic; ③ protect the health of the operator; ④ the process is simple and easy to change color; ⑤ the environment is clean and does not stain the utensils; ⑥ save time and raw materials

What does tinting power mean?

Answer: It is the ability of the colorant to affect the color of the entire mixture with its own color; when the colorant is used in plastic products, the meaning of hiding power refers to its ability to prevent light from penetrating the product.