Significant advancements have been made in the study of polymer chemical reactions since the start of the twenty-first century. Polymer materials have progressed from straightforward chemical alteration of polymers to simple blending modification of diverse polymers. Expand the application range of currently available polymer materials by enhancing the qualities of original polymers or creating polymer systems with new properties. One significant method of chemical modification is the chemical reaction of polymer components in a single-screw or twin-screw extruder. It has the qualities of being inexpensive, having a quick cycle, having a good reaction effect, and having easy large-scale production.
The reaction between maleic anhydride and polyolefin materials in the screw is currently the most often employed reaction. Polyethylene, polypropylene, and other polyolefin polymers are among examples. They are frequently utilized as all-purpose plastics due to their high output, excellent performance, and affordable pricing. However, because of its inherent flaws, including low surface energy and chemically inert molecules, its products differ from other polar polymers in that they have poor adhesion, wettability, printing and dyeing properties, paintability, antistatic properties, and gas permeability. Inorganic fillers, for example, are also poorly soluble. This demonstrates that polar non-polar polymer alloys with good properties are difficult to generate when non-polar polymers, like polyolefins, are blended with polar polymers or inorganic materials.
A little quantity of maleic anhydride can be grafted onto the polyolefin chain to considerably enhance its filling, mixing, compounding, bonding, and other qualities, hence increasing their application fields. For polymer materials, it can also be utilized as a modifier and coupling agent. Utilize solubilizers and coupling agents. For instance, only 10% of this product can be applied to polyolefin plastics to considerably increase their stickiness and paintability; when used as a reactive coupling agent for nylon reinforcement systems, it outperforms other liquid coupling agents. Excellent coupling qualities can be found in coupling agents like silane and titanate coupling agents.
Anidride maleica can be grafted onto polyolefin using a variety of techniques, including solution, melting, radiation, and solid phase processes. However, the melting method—also known as the “reactive extrusion method”—is the most crucial technique. A single-screw extruder, twin-screw extruder, or Brabender rheometer can all be used for melt grafting. With the aid of a tiny amount of dispersant, the polyolefin, MAH monomer, initiator, and other additives are well combined before being introduced to the extruder hopper for melt extrusion. The reaction of polyolefin grafting maleic anhydride is influenced by a number of variables, chief among them being the kind and concentration of the initiator, the mass concentration of the monomer, the type and concentration of the additive, the reaction temperature, the reaction time, etc. When DCP is fixed, the grafting rate shows an upward trend with the increase in the amount of MAH, but when the amount of MAH continues to increase, the grafting rate increases. As the concentration of the initiator DCP increases, the grafting rate increases accordingly, but too much DCP is used, accompanied by cross-linking reactions. When the reaction temperature is low, the concentration of DCP that decomposes is high, but it also promotes the occurrence of side reactions that consume free radicals, preventing the free radicals from significantly increasing; the melting reaction time (i.e. extruder) The grafting rate is significantly impacted by the screw’s speed. The residence period of the material in the barrel is short, the reaction is insufficient, and the grafting rate is decreased when the screw speed is too high. When the screw speed is too slow, the shear force is insufficient, which causes the initiator to be distributed unevenly. Additionally, the material residence duration is excessive, which will result in significant cross-linking and lower the grafting rate.
We creatively created and produced maleic anhydride grafted polyolefin plastics with adjustable melt index based on the preexisting conditions and the plastic multi-composite blend modification theory, which has achieved good results and advanced domestic status.
1) Process innovation: When domestically and internationally comparable products, like those made by Coace, have the same maleic anhydride grafting rate and residual amount of the same variety and material, their melt index is also a fixed value, and customers have different melting requirements depending on different usage circumstances. index. We came up with the novel idea of introducing additional additives to the formula after extensive research and analysis, which can modify the product’s melt index within a specific range to suit a variety of customer requirements.
2) Innovation in equipment: To accomplish innovation in process formulas, the granulation equipment must suitably modify the conventional structure of the past to satisfy the needs of new process formulae.
3) The formula’s most important step: Adding a melt index regulator influences the product’s melt index as well as other product indicators. There will be a lot of screening work necessary to produce the ideal indications. Additionally, it is crucial to take into account the cost and performance comparisons of the various regulators.
4) Granulation equipment internal structure adjustment: This is a crucial step in ensuring that the melt index regulator produces the maximum effect with the smallest quantity of addition.
Application horizon
Maleic anhydride molecules are attached to the polyolefin molecular chain through chemical reactions, giving the finished product not only the excellent processability and other qualities of polyolefin but also the reactivity and strong resistance of maleic anhydride polar molecules. Polar has many applications in the realm of plastics, including coupling agent, re-reaction modifier, and many others. As a filler for polypropylene and high-density polyethylene, as a coupling agent for glass fiber reinforcement, as a coupling agent between inorganic and organic pigments, and as a coupling agent between flame retardants and polyethylene, it can also be utilized in these ways.
It can also be utilized as an engineering plastics toughening modification, a carrier resin for masterbatch, a co-extruded adhesive between polyolefin and nylon, EVOH, metal, etc., or as a compatibilizer for polyolefin and nylon alloy systems. Agents, plastic mix compatibilizers, modifiers that lengthen the anti-fog lifespan of anti-fog mulch films, etc.
Maleic anhydride-grafted polyolefin can be utilized as a coupling, toughening, and compatibilizer. This substance is often added in amounts between 2 and 30%. After thoroughly mixing, the necessary high-quality products can be created using the original manufacturing method.