Synthesis of Amine and Epoxide Telechelic Siloxanes

Abstract

A synthetic route was developed to prepare thermosetting methyl, cyclopentyl, and cyclohexyl substituted polysiloxanes with epoxide or amino end groups. Cycloalkene (cyclopentene or cyclohexene) and dichlorosilane gas were reacted at 180 °C, and at high pressure (2 MPa) to produce dicycloaliphatic dichlorosilane. Hydrolytic condensations of the dichlorosilanes were performed affording low molecular weight cyclic siloxane oligomers. Base catalyzed ring opening polymerization of the cyclic oligomers afforded the hydride‐terminated polysiloxanes. The hydride‐terminated polysiloxanes were then functionalized with glycidyl epoxide or aliphatic amine groups via hydrosilation reactions. The oligomers and polymers were characterized by 1H NMR, 13C NMR, 29Si NMR, FTIR, and GPC. The molecular weight of polydimethylsiloxane, polydicyclopentylsiloxane, and polydicyclohexylsiloxane oligomers were $\overline M _{\rm n}$ = 1 000, 1 200, and 1 500, respectively. The polydispersity index of all the cyclic oligomers was ≈1.15. Differential scanning calorimetry (DSC) was used to evaluate the crosslinking reaction and the glass transition temperature of the thermally cured systems. Crosslinking occurred at 120 °C and the Tg of the methyl, cyclopentyl, and cyclohexyl functionalized siloxanes were found to be at −104, −93, and −82 °C, respectively.magnified image

A new approach to graft siloxanes to alkyds

“…41 The other unique feature of the work is the utilization of the cyclopentyl-and cyclohexyl-substituted siloxane monomers and oligomers which were developed in the Soucek laboratory. 27,42 As in a previously related study, the end properties of the cycloaliphatic-substituted siloxane coatings were enhanced as compared to methylsubstituted siloxanes. The enhanced properties of these new siloxanes are reflected in the alkyd-siloxane hybrids derived from them.…”

“…27 Phthalic anhydride (99%), pentaerythritol (98%), lithium hydroxide monohydrate (>98%), phenolphthalein, and tris(triphenylphosphine)rhodium(I) chloride (Wilkinson's catalyst) were purchased from Aldrich (Milwaukee, WI). Potassium hydroxide was purchased from Fischer Scientific.…”

Mechanical and Film Properties of Telechelic Methacrylic Polysiloxanes with Cycloaliphatic Substituents Groups for UV-Curable Applications

“…The contribution of backbone substituents outweighs the effect of crosslink density on the T g of the matrix. It is noted that the difference in T g between the thermally curable siloxanes [34] and the corresponding UVcured siloxanes is minimal. The oxygen permeability of the UV-cured dimethyldicyclopentyl and dicyclohexyl siloxane dimethacrylate cured systems are given in Table 2.…”

“…Cycloaliphatic groups on the siloxane backbone were chosen for UV-stability compared to siloxanes containing aromatic groups, and better mechanical properties than acyclic aliphatic siloxanes. The synthetic approaches for attaching methacrylic groups onto telechelic epoxide groups have been recently reported [34]. The synthesis involved ring opening of the epoxy functionality of the corresponding glycidyl epoxy telechelic siloxanes by the carboxylic acid of methacrylic acid.…”

Preparation of uniform poly(urea–siloxane) microspheres through precipitation polymerization

“…6 C) assigned to -NH-CO-NH-and -CH 2 -NH-, respectively, confirms the presence of urea group. 58 In addition, the peak of NH 2 at 1.14 ppm in APTDMS (Fig. 6 A) disappeared in S3P7 (Fig.…”