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This post was last edited by ljtjbx on 2016-12-13 at 10:00. 1. What are processing aids for polymer materials? What is its function? Answer: Additives are various auxiliary chemicals that need to be added during the production or processing of certain materials and products in order to improve the manufacturing process and enhance product performance; they are the various auxiliary chemicals required in the process of converting resins and raw rubber into plastic and rubber products. Function: ① Improve the process properties of polymers, optimize processing conditions, and enhance processing efficiency ； ②Improve the performance of products and enhance their utility and lifespan. 2. What is the compatibility between additives and polymers? What is the meaning of spray polymerization and sweating? Answer: Spray polymerization – precipitation of solid additives ； Sweating – the precipitation of liquid additives. The compatibility of additives with polymers refers to the ability of these additives to remain uniformly mixed with the polymer over time, without phase separation occurring. 3. What are dendrimeric polymer materials? Answer: Dendritic Polymers are regarded as the \"fourth new type of polymer\" material; they belong to the field of nanomaterials, which is part of the cutting-edge area of new materials. These are polymers with a dendritic structure, featuring a large number of functional groups on their surface. They possess excellent melt viscosity and offer significant possibilities for modification, which has drawn considerable attention from both the scientific community and the industrial sector. 4. What are the unique advantages of the latest fourth-generation dendrimeric polymer materials as plastic additives? Answer: As a lubricant for nylon, the modified dendrimeric polymer material differs from traditional lubricants in that it can double the processability of nylon while maintaining its mechanical properties ； As a PP toughening agent, the modified dendrimers possess flexible polyolefin long chain segments that act as connectors and buffers between molecular chains ； At the same time, dendrimers have a spherical spatial structure, resulting in a smaller hydrodynamic radius; they exhibit significantly low melt viscosity, which can **improve the melt flowability of polyolefin materials such as PP. 5. What is the function of plasticizers? Answer: Weakening the secondary bonds between polymer molecules, namely the van der Waals forces, increases the mobility of the polymer molecular chains and reduces their crystallinity. 6. Why does polystyrene have better oxidation resistance than polypropylene? Answer: The unstable H is replaced by a large phenyl group; the reason why PS does not age easily is that the benzene ring acts as a shield for H ； PPs containing tertiary hydrogens age easily. 7. What are the reasons for the thermal instability of PVC? Answer: ① The molecular chain structure contains initiator residues comprising allyl chloride, which acts as an activating group; the terminal double bonds reduce thermal stability ； ②The effect of oxygen accelerates HCl release during the thermal degradation of PVC ； ③The HCl produced by the reaction acts as a catalyst for the degradation of PVC ； ④Effect of plasticizer dosage. 8. Based on current research findings, what are the main functions of heat stabilizers? Answer: ① Absorb and neutralize HCL, thereby suppressing its autocatalytic effect ； ②Replace the unstable allyl chloride atoms in PVC molecules to inhibit the release of HCl ； ③It undergoes addition reactions with polyene structures, disrupting the formation of large conjugated systems and reducing coloring ； ④Capture free radicals and prevent oxidation reactions ； ⑤Neutralization or passivation of metal ions or other harmful substances that catalyze degradation ； ⑥It provides protection against ultraviolet radiation, shielding and reducing its effects. 9. Why is ultraviolet light the most destructive to polymers? Answer: Ultraviolet light has a short wavelength and high energy, which breaks most of the chemical bonds in polymers. 10. To which category of synergistic systems do intumescent flame retardants belong, and what is their basic principle of action? Answer: Expansive flame retardants belong to the phosphorus-nitrogen synergistic system. Mechanism: When polymers containing this flame retardant are heated, a uniform layer of carbonaceous foam is formed on their surface. This layer provides insulation, blocks oxygen, suppresses smoke generation, and prevents dripping, thereby granting the material excellent flame retardant properties. 11. What is the oxygen index, and what is the relationship between its value and flame retardancy? Answer: OI = O2/(O2+N2)×100%, where O2 is the oxygen flow rate ； N2: Nitrogen flow rate. The oxygen index refers to the minimum volume percentage of oxygen required in a nitrogen-oxygen mixture for a specimen of a certain specification to burn steadily in a candle-like manner. OI