Two Modification Methods of Polysiloxane
Aug 3, 2023
Synthesized using aminoethylaminopropyl polydimethylsiloxane (CAE-PS), 2,4-toluene diisoacrylate (TOI), polypropylene glycol (NZOO) and dihydroxymethylpropionic acid (DMPA). For water-based polyurethane, the study found that after modification, the glass transition temperature of both hard and soft segments increases, and the increase of the hard segment is more obvious than that of the soft segment. The organosilicon is suspended on the side chain of the polyurethane hard segment, which has little effect on the molecular structure of the soft segment, so that the glass temperature of the soft segment does not increase much, and in the material modified by organosilicon - NH is a proton donor, which increases The formation of hydrogen bonds improves the driving force of microscopic phase separation, makes the phase separation of soft segment and hard segment more perfect, and the glass transition temperature of the hard segment phase increases significantly.
A series of polyurethanes with different siloxane contents were synthesized from MDI, PTMO, aminoethylaminopropyl polydimethylsiloxane (AEAPS) and BO as main raw materials. It was found that the concentration of siloxane units in the surface area of the elastomer was higher than that in the bulk due to the surface enrichment of siloxane, and the tensile strength of the polyurethane elastomer modified with AEAPS was not significantly improved. Variety.
Synthesis of Organosilicon Modified Polyurethane Prepolymer
Using TOI, PPG and AEAPS as raw materials, silicone-modified polyurethane prepolymer was synthesized under solvent-free conditions, and amino silicone oil-modified polyurethane material was obtained with MOCA as curing agent. The research results show that the modified polyurethane has the best effect when the mass content of silicone oil is 10%. Using TOI and PPG as main raw materials to prepare an NCO-terminated prepolymer, and mix it with epoxy resin E-51 in a certain proportion; in addition, synthesize aminopolysiloxane, and use polyamines as curing agent to synthesize a A series of aminopolysiloxane modified polyurethane/epoxy interpenetrating network polymers. This material is a new type of low surface energy material with good hydrophobic properties, and the change of its mechanical properties is closely related to the content and molecular weight of aminopolysiloxane.
(2)Amino linear modification
Amino straight-chain modification is a method in which amino groups are connected to both ends of siloxane and modified by embedding siloxane into the main chain of polyurethane through the reaction of amino groups. The terminal oligomers were copolymerized into amino silicone oil-modified polyurethane coatings, and salt spray experiments were carried out on its anti-corrosion properties. It was found that the modified polyurethane coatings had greatly improved anti-corrosion properties on copper.
The permeability of block copolymers to gases and liquids is reviewed, and the cross-linked copolymers prepared with aminopropyl-terminated PDMS/MDUBD are mentioned as separation membranes for ethanol/water mixtures, which only allow ethanol to pass through, and The separation coefficient is related to the busyness of PDMS. Because siloxane is embedded in the main chain, its migration ability is affected. Therefore, the content of silicone and the length of the chain segment have a great influence on the performance after modification. Amino-alkyl end-capping modification method. Since there is more than one reactive group attached to N, a cross-linked structure will be formed after reacting with isophenolic acid ester. Difficult to disperse in water.
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