Triol crosslinking agent

The product is called l,l,l—Trimethylolpropane (TMP) and is used mainly in the manufacture of triols by adduction with propylene oxide (PO), for flexible polyurethane foams and of synthetic lubricants by esterification with fatty acids. The allyl ethers of trimethylolpropane are used as crosslinking agents, for example, in acrylic resin systems. The world-wide capacity for TMP production is in an increasing trend. 

A well known triol, tris (hydroxyethyl) isocyanurate (THEI) is produced industrially and currently used in PU manufacture, as a crosslinking agent (15.47) [31, 41]. 

The obtained theoretical predictions have been verified in experiments on real elastomers. The elastomers tested in our experiments were amorphous polybutadiene urethanes (PBU) wifli polymer network of different density 0.3 kmol/m (PBU-1), 0.05 kmol/m (PBU-2), 0.2 kmol/m (PBU-3), 0.1 kmol/m (PBU-4). Oligooxypropylene triol - Laprol 373 was used as a crosslinking agent at the curing of prepolymer of oligobutadiene diol. The elastomer specimens were manufactured in the form of disks, 35 mm in diameter and 2 mm thick. The kinetics of specimen swelling was determined in low-molecular liquids toluene, dibutyl sebacate (DBS), dioctyl sebacate (DOS). 

Because the ketene acetal-terminated prepolymer is a viscous Liquid at room temperature, therapeutic agents and the triol can be mixed into the prepolymer at room temperature and the mixture crosslink id at temperatures as low as 40°C. This allows incorporation of heat-sensitive therapeutic agents into a solid polymer under very mild conditions of thermal stress. However, because the prepolymer con-tedns reactive ketene acetal groups, any hydroxyl groups present in the therapeutic agent will result in the covalent attachment of the therapeutic agent to the matrix via ortho ester bonds (16). 

Crosslinked poly(ortho esters) are prepared by a reaction sequence in which an excess of the diketene acetal 3,9-bis(ethylidene 2,4,8,10-tetraoxaspiro [5,5] undecane) is reacted with a diol, and the ketene acetal terminated prepolymer is then crosslinked with a triol. Because the prepolymer is a viscous liquid at room temperature, the therapeutic agent and any excipients used are incorporated into the prepolymer by mixing at room temperature and then cured at temperatures that can be as low as 40°C. 

The synthesis and characterization of four distinct families of poly (ortho esters) are described and designated as poly (ortho esters) I, II, III and IV. Poly (ortho ester) I is prepared by the transesterification of diethoxytetrahydrofuran with diols. Poly (ortho ester) II is prepared by the condensation of 3,9-bis (ethylidene 2,4,8,10-tetraoxaspiro [5, 5] undecane) with diols to produce a linear polymer or with a triol to produce a crosslinked polymer. Poly (ortho ester) III is prepared by the condensation of a flexible triol with and alkyl orthoacetate to produce ointment-like materials. Poly (ortho ester) IV is prepared by the condensation of a rigid triol with and alkyl orthoacetate to produce solid materials. The detailed mechanism of hydrolysis of these polymers has been determined and drug release data for a number of therapeutic agents are presented. 

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