Telechelic polydimethylsiloxanes with terminal acetylenic groups prepared by phase-transfer catalysis

Telechelic, hydroxyalkyl terminated polydimethylsiloxanes were obtained under mild conditions via hydrosilylation of allyl alcohol or ethylene glycol monoallyl ether by oligomeric αω-hydride terminated polydimethylsiloxanes, with the use of a platinum catalyst. They were subsequently modified in a phase transfer catalyzed reaction by propargyl bromide, to give telechelic polysiloxanes terminated by acetylenic groups. The synthetic pathway is described and the characterization of the obtained products is presented.     

Syntheses of triblock polybutadiene–polydimethylsiloxane copolymers by coupling reactions

The reaction of epoxy‐telechelic polydimethylsiloxanes with polybutadienyllithium was used to prepare a series of low‐molecular‐weight polybutadiene‐block‐polydimethylsiloxane‐block‐polybutadiene copolymers. The copolymers were purified by repeated fractional precipitation/centrifugation and characterized with NMR, vapor pressure osmometry, size exclusion chromatography, and elemental analysis. The applicability of this method is discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3233–3240, 2006     

Polysiloxanes containing crosslinkable diacetylene units in the main chain

The oxidative coupling of telechelic [2‐(propyn‐1)oxyethyl]oxypropyl‐terminated polydimethylsiloxanes, with the use of copper (I) chloride/TMEDA complex as the coupling catalyst, is described. The results of the studies on the influence of the reaction parameters (the catalyst concentration, the oxygen flow‐rate and the nature of the solvent) are presented. UV curing of the polymers obtained in the course of the oxidative coupling is reported Copyright © 2003 Society of Chemical Industry     

Modification of cyclohexanone–formaldehyde resins with silicone tegomers

Cyclohexanone–formaldehyde resins were modified in situ with α,ω‐diamine polydimethylsiloxanes and α,ω‐dihydroxy polydimethylsiloxanes. Melting points, solubilities in organic solvents, gel permeation chromatographs, Fourier transform infrared spectra, and NMR spectra of the modified resin were determined, and the surface properties of the resins were investigated by contact angle measurements. A small amount of silicon compounds seemed to effect the physical properties of the cyclohexanone–formaldehyde resins significantly. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 97–101, 2005     

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

A series of novel reactive polydimethylsiloxanes (PDMS) bearing hydroxypropyl group at both chain ends and carbonyl groups at the side chain were incorporated with toluene 2,4-diisocyanate, dimethylol propionic acid and polypropylene glycol by the prepolymer process to synthesize a series of reactive PDMS-modified waterborne polyurethanes. After post-added dihydrazide, self-crosslinking was achieved by the reaction between the dihydrazide and carbonyl group during film formation. The latex film properties of them were investigated compared with that of pure waterborne polyurethane. Crosslinking was indeed enhanced in the films. Tensile strength, elongation at break and higher performance in water and solvent adsorptions were also detected.     

二甲基氯硅烷的合成及应用

本文介绍了二甲基氯硅烷（Ｍｅ＿２ＳｉＨＣｌ）的合成方法，由它制备Ｈ－封端聚甲基硅氧烷以及用于改性有机聚合物的活性硅油。     

羟烃基聚硅氧烷的制备及亲水性能

以八甲基环四硅氧烷(D4)、四甲基环四硅氧烷(D4H)和六甲基硅氧烷(MM)为原料实施开环聚合反应,制备出不同含氢量的聚二甲基硅氧烷;含氢硅氧烷与乙酸乙烯酯进行硅氢加成反应,在硅氧烷大分子侧链上引入酯基;然后碱性条件下进行醇解反应,最后成功合成了不同羟烃基含量的聚硅氧烷.对产物的结构、乳化稳定性、乳液粒径及成膜的表面性...     

Polydimethyldiphenylsiloxanes/silica interconnected networks: preparation and properties evaluation

A series of copolymers, polydimethyldiphenylsiloxane-α,ω-diols, differing by compositions and molecular masses has been prepared by equilibrium anionic ring-opening copolymerization of octamethylcyclotetrasiloxane with octaphenylcyclotetrasiloxane in presence of tetramethylammonium hydroxide as a catalyst. These copolymers were used as matrix for the in situ developing silica networks. The crosslinking of the copolymers concomitantly occurs by reaction between the ending silanol groups and tetraethoxysilane, thus the polydiorganosiloxane network interconnects with the silica one. The resulted materials processed as films (thickness 0.25–1.50 mm) were investigated by various techniques in order to evaluate morphology, optical properties, and thermal behavior. The results were compared with those obtained by model samples based on polydimethylsiloxanes/silica.     

有机硅改性聚氨酯合成革涂饰剂的合成及性能

用聚醚多元醇(PPG)、聚二甲基硅氧烷(PDMS)、异佛尔酮二异氰酸酯(IPD I)、1,4-丁二醇(BDO)等为主要原料,合成了有机硅改性聚氨酯溶液。通过对合成条件的考察发现,反应温度为65℃,反应4 h,采用m(丁酮)∶m(二甲苯)=1∶1作溶剂,可得到黏度适中、性能良好的产品。考察了聚二甲基硅氧烷质量分数〔w(PDMS)〕对有机硅改性聚氨酯溶液及其成膜性能的影响。结果发现,随着w(PDMS)增加,溶液的黏度降低,成膜的热稳定性提高,当w(PDMS)=10%时成膜的水接触角达到最大值102.6°。     

Synthesis of α,ω-hydroxyalkyl telechelic polydimethylsiloxane soft segments and preparation of waterborne polyurethane–polydimethylsiloxane block copolymers

In this paper, by optimizing synthesis process of α,ω-hydroxyalkyl telechelic polydimethylsiloxane, α,ω-bis(3-(1-methoxy-2-hydroxypropoxy)propyl)polydimethyl siloxane (PMTS), the yield of hydrosilylation product, 1,3-bis(glycidoxypropyl) tetramethyldisiloxane exceed 86.5%. By tracing the change of methanol (gravimetry) and measuring the change of molecular weights of polydimethylsiloxanes at different reaction time (titration), the optimum reaction time of methoxylation reaction and ring-opening polymerization was determined as 8 and 12 h. Using α,ω-bis(3-(1-methoxy-2-hydroxypropoxy)propyl)polydimethyl siloxane with different molecular weights, waterborne polyurethane–polydimethylsiloxane block copolymer were prepared. The influences of molecular weights and content of α,ω-hydroxyalkyl telechelic polydimethylsiloxane on the waterborne polyurethane–polydimethylsiloxane block copolymers were investigated in detail. The addition of α,ω-hydroxyalkyl telechelic polydimethylsiloxane could improve the water-resistance property obviously and increase the elongation at break. However, the mechanical property was reduced with increase of content and molecular weight of α,ω-hydroxyalkyl telechelic polydimethylsiloxane.     

Self‐healing supramolecular elastomers based on the multi‐hydrogen bonding of low‐molecular polydimethylsiloxanes: Synthesis and characterization

Novel self‐healing supramolecular elastomers based on polydimethylsiloxanes (SESi) were synthesized from a mixture of polydimethylsiloxanes derivers with single, di‐, or tri‐carboxylic acid groups (PDMS–COOH_x, where x = 1, 2, and 3, respectively), diethylene triamine, and urea with a two‐stage procedure. The reactions and the final products were tracked, characterized, and confirmed by Fourier transform infrared spectroscopy, ¹H‐NMR, differential scanning calorimetry, dynamic mechanical analysis, and gel permeation chromatography. Compared with a supramolecular rubber based on dimer acid (reported previously) with a similar synthesis procedure, the SESi showed a lower glass‐transition temperature of about ?113°C for the softer chain of polydimethylsiloxane and showed real rubberlike elastic behavior and self‐healing properties at room temperature or even lower temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

合成革用有机硅改性脂肪族聚氨酯树脂的合成及应用

采用聚酯多元醇、异佛尔酮二异氰酸酯(IPDI)、聚醚改性聚硅氧烷(PO-PDMS)等为主要原料合成了有机硅改性脂肪族聚氨酯树脂.考察了不同有机硅含量对聚合物状态、力学性能、耐水性和耐黄变性能的影响,以及有机硅改性脂肪族聚氨酯树脂在合成革上的应用性能.结果表明,相对于物理共混,将PO-PDMS与聚氨酯共聚可有效提高有机硅...     

Verstärkung von Polysiloxanen mit Thermoplasten

Radical polymerization of organic monomers in room-temperature curable polydimethylsiloxanes (PDMS) yields liquid dispersions of thermoplastic polymers in PDMS. Graft copolymers of organic polymers and PDMS generated in the polymerization stabilize these dispersions like nonionic surfactants and act as a link between organic polymer particles and PDMS-matrix after vulcanization. This linkage and the special, rod-like shape of the polymer particles cause reinforcing effects, leading to vulcanizates that show unusual toughness in comparison to ordinary silicone rubber.     

Synthesis of polysiloxane–polyester copolymer by lipase‐catalyzed polycondensation

Polysiloxane–polyester copolymers have been synthesized for the first time by direct polycondensation of a series of diacids (butanedioic, hexanedioic, and octanedioic acid) and α,ω‐bis(3‐hydroxypropyl) polydimethylsiloxanes catalyzed with Novozyme‐435 in high yields (>90%) without the cleavage of Si? O bonds. The effects of monomer chain length, reaction temperature, and water removal method on the number–average molecular weight (M_n) of the resulted copolymers were investigated. Thermogravimetric and differential scanning calorimetry analyses indicated that the produced copolymer was more thermally stable than poly(1,8‐octyladipate) and the T_g was lowered to ?111°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,thermal, and dynamic mechanical properties of 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane‐containing polydimethylsiloxanes

New and effective approaches to the synthesis of 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane‐containing polydimethylsiloxanes ( P1 and P2 ) were developed. P1 was obtained by polycondensation of cyclodisilazane lithium salt and chloroterminated polydimethylsiloxane. P2 was produced by hydrosilylation of vinyl‐terminated cyclodisilazane and hydrogen‐terminated polydimethylsiloxane. The polycondensation completed quickly at room temperature, while the hydrosilylation was facile and did not require cumbersome air‐sensitive operations. P1 and P2 were characterized by Fourier transform infrared, nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis (TGA), and isothermal gravimetric analysis (IGA). TGA revealed the outstanding thermal properties of P1 and P2 with 5% weight loss temperatures (T_d5) higher than 450°C. IGA proved their better thermal stability at 450°C for 800 min, compared to polydimethyldiphenylsiloxane. Dynamic mechanical analysis showed that silicone rubbers made from cyclodisilazane‐containing polydimethylsiloxanes could have a maximum tan δ value as high as 1.13 and had good prospects for damping material applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Supramolecular association of acid terminated polydimethylsiloxanes

Summary. Benzoic acid terminated polydimethylsiloxanes (PDMS) have been synthesized by hydrosilylation of allyloxybenzylbenzoate with SiH terminated precursors followed by deprotection. These oligomers have been characterized by ¹H, ¹³C and ²⁹Si NMR, by FTIR and by SEC in tetrahydrofurane. Because of the flexibility and low polarity of the siloxane backbone, they are ideally suited to study the effect of hydrogen bonding on macromolecular properties. Received: 17 July 1997/Revised: 22 July 1997/Accepted: 6 August 1997     

Photocrosslinking of chlorinated polydimethylsiloxanes

Photocrosslinking behavior of chlorinated polydimethylsiloxanes (C-PDMS) has been studied. It was found that the viscous C-PDMS were readily crosslinking to form the rubberlike materials on irradiation from a high pressure mercury lamp. The crosslinking mechanism was proposed on the basis of infrared spectroscopy. It was suggested that the photolysis of the carbon—chlorine bond induced by the ultraviolet irradiation is a primary step for crosslinking, and is followed by mutual combination of SiCH_2· radicals, eventually, to form the crosslinked C-PDMS. The effect of halogens and atmosphere on the crosslinking was also discussed.     

Controlled drug release of silicone‐based adhesive‐containing cross‐linked siloxane powders as a reservoir

We prepared pressure‐sensitive adhesive (PSA)‐containing cross‐linked siloxane powders (CS) as a reservoir for a transdermal drug delivery system (TDDS) and evaluated their sustained drug‐release properties. PSA, as a patch‐type adhesive, was synthesized by a hydrosilylation reaction of vinyl‐terminated polysiloxanes with hydrogen‐terminated polydimethylsiloxanes. CS was also prepared via a hydrosilylation process with vinyl‐terminated polydimethylsiloxane, 1,3,5,7‐tetramethyl‐1,3,5,7‐tetravinyltetracyclosiloxane ( ), hydrogen‐terminated polydimethylsiloxane, and dimethylhydrogenmethyl oligomeric siloxane copolymer. The results of release performances using ascorbic acid as a model drug showed a cumulative linear slope over a week, indicating a constant release performance. Our data suggest that this siloxane TDDS could be useful for constant drug release over a long period. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42154.     

Tetramethylammonium 3-aminopropyl dimethylsilanolate—aminopropyl dimethylsilanolate—a new catalyst for the synthesis of high purity,high molecular weight α,ω-bis(aminopropyl) polydimethylsiloxanes

Tetramethylammonium 3-aminopropyl dimethylsilanolate, readily prepared from bis(3-aminopropyl) tetramethyldisiloxane and tetramethyl-ammonium hydroxide pentahydrate, has been found to serve as a highly effective catalyst for the ring opening polymerization of cyclic siloxanes with an end blocker such as bis(3-aminopropyl) tetramethyldisiloxane to give aminopropyl terminated linear polydimethylsiloxanes. By following a novel two stage procedure, even high molecular weight (5,000–55,000 g/mol) silicone diamines were able to be prepared in a high state of purity; chain extension reactions of these diamines with diisocyanates gave a series of high molecular weight silicone polyureas with good elastomeric properties.