Modification of Water-soluble Silicone Polyurethane

Using polyester silicon (polyester) polyol, organic low molecular weight, polyisonitroester, chain extender and hydrophilic chain extender as main raw materials, siloxane copolymerized polyurethane emulsion PU-SI was prepared. FT-IR, NMR, Porous Permeation Chromatography (GPC), Electron Spectroscopy (ESCA), Contact Angle Meter, Electronic Tensile Testing Machine, etc. were used to characterize and analyze the chemical structure and properties of the synthesized products.

The results show that the silicone-modified polyurethane emulsion has good stability, and the siloxane segment can be enriched on the surface of the emulsion film, which has an obvious surface modification effect on the polyurethane material and improves the water resistance, while the bulk mechanical properties do not change. Large, good overall performance as a top coat.

The water-soluble silicone (ROCH type pressure OH) is modified by end-blocking polyurethane, the TOI is first blocked with phenol, and then reacted with water-soluble silicone, and then emulsified with water to obtain a reactive fabric finishing agent, which is elastic and washable sex is better. Water-soluble silicone is a silicone emulsion made by grafting hydrophilic groups such as polyoxyethylene ester chains on polysiloxane chains and modifying them.

The researchers pointed out in the patent: Use PDMS containing hydroxyalkyl or aminoalkyl end caps and side chains to modify polyurethane and make aqueous emulsions, which can be cationic, anionic or nonionic emulsions, as phase-forming Elemental surface protection layer consisting of water-based paints.

Polyurethane block polymers were synthesized with bishydroxybutyl-terminated polydimethylsiloxane as the soft segment, and the hard segment was BD or N-methyldiethanolamine-extended MDI segment. These copolymers all exhibit almost complete phase separation. Copolymer materials exhibit ionic aggregation within the hard segment domains. Crystallization of hard segments or aggregation of ions does not affect the morphology. The cohesion of the hard segment domains is more influential than the volume fraction of the hard segment in determining the tensile and viscoelastic properties of these elastomers.

The researchers prepared polysiloxane diol, and then reacted with IPDI, light ethyl methacrylate and neopentyl glycol or ethylene glycol to prepare a polyurethane prepolymer, and the film obtained after UV curing had better Excellent mechanical properties and high oxygen permeability. Hydrogen-containing silicone oil and allyl alcohol are used as raw materials to synthesize hydroxypropyl silicone oil, and then synthesize organic silicon/acrylate/polyurethane resin, and formulate UV-curable coatings.

The aliphatic polyurethane elastomer was prepared from H-MDI and a, (hydroxyethoxypropyl) polydimethylsiloxane and poly(hexamethylene oxide) mixed diol as main raw materials. BD is the primary chain extender. Several secondary chain extenders are selected. The polyurethane elastomer produced has low flexural stiffness and good tensile strength.

The synthesis method, structural characteristics and properties of silicone-modified polyurethane are reviewed, phase separation and its influence on material properties and ways to increase compatibility are discussed, and its application is briefly introduced, and the process of addition polymerization is also mentioned. To choose a suitable solvent.

Other modification methods of polyurethane

In addition to the methods introduced above, many modification methods have been studied to further improve the performance and range of use of polyurethane. Preparation of polyester intercalated organic montmorillonite Y-2-aminopropyl-ethoxysilane, and reaction to obtain WPU prepolymer with significantly improved mechanical properties and water resistance.

With H containing silicone oil, unsaturated polyester undergoes hydrosilylation first to obtain organosilicon modified lotion that is stable at room temperature and has particle size diameter of about 50 and 100 nm. PU/MMT modified composite materials were prepared using montmorillonite (MMT) modified with siloxane diamine and diphenylmethane diisocyanate (MDI) as raw materials. Research has found that the strength and modulus of PU/Organo MMT modified with organic silicon have significantly increased compared to PU/Na+- MMT due to the formation of an incomplete delamination intercalation structure in PU.

Polysiloxane/polyurethane IPN modified, interpenetrating polymer network ­ Mer Network, also known as IPN, is not a simple mechanical blending between polymers, nor is it formed through chemical bonding, blocking, or grafting, nor is it an association compound generated by intermolecular attraction. It is an interlocking network formed by the penetration, interweaving, and entanglement of different polymer molecular chains, and cannot be separated without cutting off the polymer molecular chains. Polyurethane materials are prone to chain growth and crosslinking due to the high activity of their precursor prepolymers.

In summary, the modification of polyurethane by organic silicon can indeed combine the excellent properties of both. It not only maintains the characteristics of polyurethane material such as wear resistance, good elasticity, and strong solvent resistance, but also integrates the advantages of organic silicon resin such as low tenderness, good smoothness, low surface tension, and strong hydrophobicity. The advantage of chemical modification method lies in reasonable molecular structure design and the development of composite modification technology, which includes block, graft The organic combination of modification methods such as interpenetrating networks and core-shell polymerization can produce materials with better performance through two or more of these modification methods, in order to expand their application fields. Its research prospects are very broad and need further development and application.

However, there are still two issues that restrict its application: firstly, the compatibility between the two is poor, and there is a phenomenon of phase separation. It is necessary to choose an appropriate degree of phase separation to improve the material's performance; Secondly, organic silicon raw materials are expensive. In contrast, polyurethane modified with hydroxyalkyl polysiloxane exhibits excellent performance. However, the preparation of this type of polysiloxane is still relatively difficult and there is no large-scale production, which is also the two focus of future research on silicone modified polyurethane.

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