In this article, Qingdao Sainuo polyethylene waxmanufacturer will take you to know the relevant knowledge of plastic processing additives.

1. What are polymer processing aids? What is its function?

Additives are various auxiliary chemicals that need to be added in the production or processing of some materials and products to improve the production process and product performance. They are various auxiliary chemicals required in the process of processing resin and raw rubber into plastic and rubber products.

2. What is the compatibility between additives and polymers? 

The compatibility of additives and polymers refers to the properties of the additives and polymers which can be mixed uniformly and together for a long time without separation of production phases;

3. What is the role of plasticizers?

Weaken the subvalent bond between polymer molecules, that is, van der Waals force, so as to increase the mobility of polymer molecular chain and reduce the crystallinity of polymer molecular chain.

4. Why is polystyrene better oxidation resistant than polypropylene?

Unstable h is replaced by huge phenyl. The reason why PS is not easy to age is that the benzene ring has a shielding effect on H; PP contains tertiary hydrogen, which is easy to age.

5. What is causes of instability of PVC during heating?

① The molecular chain structure contains initiator residues and allyl chloride plays the role of activating group, and the end group double bond reduces the thermal stability; ② The effect of oxygen accelerated the removal of HCl during the thermal degradation of PVC; ③ HCl produced by the reaction can catalyze the degradation of PVC; ④ The amount of plasticizer.

6. Based on the current research results, what are the main functions of heat stabilizers?

① Absorb and neutralize HCl to inhibit its autocatalysis; ② Replace the unstable allyl chloride atom in PVC molecule to inhibit the removal of HCl; ③ The addition reaction with polyene structure destroys the formation of large conjugated system and reduces coloring; ④ Capture free radicals and prevent oxidation reaction; ⑤ Neutralizing or passivating metal ions or other harmful substances that catalyze degradation; ⑥ It can protect, shield and weaken ultraviolet radiation.

7. Why is UV most damaging to polymers?

Ultraviolet waves are long and powerful, breaking most polymer chemical bonds.

8. Why is UV most damaging to polymers?

Intumescent flame retardant belongs to phosphorus nitrogen synergistic system.

Mechanism: when the polymer containing the flame retardant is heated, a uniform carbon foam layer is formed on the surface, which is heat insulating, oxygen isolating, smoke suppressing and dripping proof, so it has good flame retardancy.

9. What is the oxygen index? What is the relationship between the oxygen index and flame retardancy?

OI=O2/(O2 N2) × 100%, where O2: oxygen flow; N2: nitrogen flow. Oxygen index refers to the volume percentage of the lowest oxygen required in the nitrogen oxygen mixture when a certain specification sample can burn continuously and stably like a candle. Oi < 21 is flammable, OI is 22 ~ 25, self extinguishing, 26 ~ 27 is flame retardant, and above 28 is extremely flame retardant.

10. According to the current research, what are the mechanism of the flame retardant?

① The decomposition products of flame retardant at combustion temperature form non-volatile and non-oxidation glass films, which can isolate the reflection energy of air or have low thermal conductivity.

② The flame retardant decomposes to generate non combustible gas, so as to dilute the combustible gas and dilute the oxygen concentration in the combustion area;

③ Heat consumption of flame retardant by melting and decomposition;

④ Flame retardant promotes the formation of a porous thermal insulation carbon layer on the plastic surface to prevent heat conduction and continuous combustion.

11. Why is it easy for plastics to carry static electricity during processing or use?

Because the molecular chains of the main polymer are almost composed of covalent bonds, they can neither ionize nor transfer electrons. In the process of its processing and product use, 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 is difficult to disappear through its own conduction.

12. What are the characteristics of the molecular structure of antistatic agents?

R-Y-X. R: lipophilic group, Y: connecting group, X: hydrophilic group. In their molecules, there should be an appropriate balance between the lipophilic group of the non-polar part and the hydrophilic group of the polar part, and have certain compatibility with polymer materials. Alkyl groups above C12 are typical lipophilic groups, while hydroxyl, carboxyl, sulfonic acid and ether bonds are typical hydrophilic groups.

13. The action mechanism of antistatic agent is briefly described

First, the antistatic agent forms a conductive continuous film on the surface of the material, that is, it can give the product surface a film with certain moisture absorption and ionic properties, so as to reduce the surface resistivity and quickly leak the generated electrostatic charge, so as to achieve the purpose of antistatic; The second is to give the material surface a certain lubricity and reduce the friction coefficient, so as to inhibit and reduce the generation of electrostatic charge.

14. What changes usually occur in the structure and properties of rubber after vulcanization?

① Vulcanizate changed from linear to three-dimensional network structure; ② Heating no longer flows; ③ No longer soluble in its good solvent; ④ Increased modulus and hardness; ⑤ Improved mechanical properties; ⑥ Aging resistance and chemical stability are improved; ⑦ Media performance may degrade.

15. What is the role of vulcanization accelerator?

Improve the production efficiency of rubber products, reduce costs and improve performance. A substance that promotes vulcanization. It can shorten the curing time, reduce the curing temperature, reduce the amount of curing agent and improve the physical and mechanical properties of rubber

16. Scorch phenomenon

It refers to the early vulcanization of rubber compound during processing.

17. The function and main varieties of vulcanizing activator are briefly described

Function of active agent - enhance the activity of accelerator, reduce the dosage of accelerator and shorten the vulcanization time.

Active agent: a substance that can increase the activity of organic accelerators and make them fully effective, thus reducing the dosage of accelerators or shortening curing time. The active agents are generally divided into two types: inorganic active agent and organic active agent. The inorganic active agents mainly include metal oxides, hydroxides and alkali carbonate; Organic active agents mainly include fatty acids, amines, soap, polyols and amino alcohols. The vulcanization degree of the active agent can be improved only by adding a small amount of the active agent into the rubber compound.

18. What is the aftereffect of accelerators and what kind of accelerators have good aftereffect?below the vulcanization temperature, it will not cause early vulcanization. When it reaches the vulcanization temperature, it has great vulcanization activity. This property is called the post effect of accelerator. Sulfosamides have good aftereffect.

19. Definition of lubricant and the difference between internal and external lubricants?

Lubricant - an auxiliary agent that can improve the friction and adhesion between the particles in each layer of plastic and between the melt and the metal surface of processing equipment, increase the fluidity of resin, regulate the plasticization time of resin and maintain continuous production, 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 purpose of easy processing and molding without damaging the plastic performance. Internal lubricant can reduce the internal friction of polymer, increase the melting rate and melt deformation of plastic, reduce melt viscosity and improve plasticization performance.

The difference between internal and external lubricants: the internal lubricant requires better compatibility with polymer, reduces friction between molecular chains and improves flow performance; The external lubricant requires compatibility with polymer, reducing friction between polymer and machined surface.

20. What are the factors that determine the effect of filler reinforcement?

The reinforcement effect depends on the bulk structure of the plastic itself, the amount of filled particles, specific surface and size, surface activity, particle size and distribution, phase structure, and the aggregation, dispersion and dispersion of particles in polymers. The most important is the interaction between the filler and the interface layer formed by the polymer chain, which includes not only the physical or chemical force of the particle surface on the polymer chain, but also the crystallization and orientation of the polymer chain in the interface layer.

21 What factors affect the strength of reinforced plastics?

① The strength of the reinforcing agent is selected to meet the requirements; ② The strength of basic polymers can be met through the selection and modification of polymers; ③ Surface adhesion of plasticizer and basic polymer; ④ Tissue material of reinforcing material.

22. What is the coupling agent, its molecular structure characteristics, and give examples to illustrate the action mechanism

Coupling agent refers to a kind of material that can improve the interface characteristics between filler and polymer materials.

There are two functional groups in its molecular structure: one can react with polymer matrix or at least have good compatibility; The other can form chemical bonds with inorganic fillers.

23. What is foaming agent?

Foaming agent is a kind of material that can make rubber and plastic in liquid or plastic state in a certain viscosity range form microporous structure.

Physical foaming agent: a kind of compound that achieves foaming purpose by relying on the change of its own physical state in the foaming process;

Chemical foaming agent: it will thermally decompose at a certain temperature to produce one or more gases to make the polymer foam.

24. What is color masterbatch?

Color masterbatch is an aggregate made by uniformly attaching super constant pigments or dyes to resin;

Basic composition: pigment or dye, carrier, dispersant, additive;

Functions: ① it is conducive to maintaining the chemical stability and color stability of pigments; ② Make pigments have better dispersibility in plastics; ③ Protect the health of operators; ④ Simple process and easy color conversion; ⑤ The environment is clean and does not contaminate the utensils; ⑥ Save time and raw materials.

25. What is coloring power?

Coloring power is the ability of colorant to affect the color of the whole mixture with its own color; When colorants are used in plastic products, the meaning of hiding power refers to its ability to prevent light from penetrating the products.

Qingdao Sainuo Chemical Co., Ltd. We are manufacturer of PE wax, PP wax, OPE wax, EVA wax, PEMA, EBS, Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing. 

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