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Polypropylene - Nucleating Technology |
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Throughout the past decade, Polypropylene is the most widely use polymers among all due to its cost effectiveness. Thus, it is always the hot issue for Polypropylene modification. People tend to modify PP by (1) improving its clarity, or (2) improving its impact strength and heat resistance.
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Traditionally, impact modifiers are mixed with PP to improve its impact strength. However, it will cause the decrease in heat resistance. By adding inorganic fillers, the Heat Distortion Temperature of PP will be increased, on the other hand, it will weaken the impact strength. To get rid of this dilemma, changing the crystallization of PP becomes the way for breakthrough. |
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Polypropylene is a semi-crystalline polymer, with three forms co-exiting in all types of PP: alpha phase (£\-phase), beta phase (£]-phase) and gamma phase (£^-phase). |
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Polymer modification of PP is by controlling the size and shape of crystal formed. Such as, by lowering the size of £\-crystalline could improve the clarity of PP; by increasing the content of £]-crystalline would enhance its impact strength. |
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NA-21 is the latest PP Clarifying Agent. It induces PP to form small size £\-crystalline which improve the gloss, stiffness, and heat resistance of the final product. |
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IM-35 is the latest PP Impact Modifying Agent. With small quantity of IM-35, PP would tend to form with £]-crystalline in nearly 90%. It significantly increases the impact strength and heat resistance of the final product. |
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£\- phase |
£]- phase |
£^- phase |
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| Monoclinic, the most stable and the most well-known form |
Metastable, pseudo-hexagonal, mainly found in Block-Co-Polymer PP. Presence of £] -phase in Homo PP generally increases ductility of finished parts. |
Metastable, with triclinic crystals, not very familiar but appears mainly in low molecular weight PP by crystallization at very high pressure and very low cooling rate. |
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