Synthesis of UV-curable polysiloxanes containing methacryloxy/fluorinated side groups and the performances of their cured composite coatings

Three novel UV-curable polysiloxanes consisting of polysiloxane backbone with methacryloxy/fluorinated side groups were synthesized, and their structures were characterized by FT-IR, ¹H NMR and ¹³C NMR. A series of UV-cured composite coatings based on the synthesized polysiloxanes and an epoxy methacrylate were obtained through photopolymerization. Their gel content, flexibility, hardness, gloss, contact angle, thermal behavior as well as water absorption ratio were investigated. Results found that the siloxane component could enhance the flexibility and gloss of coatings, while the presence of fluorinated groups could improve the hardness. The combination of silicon and fluorine in the same polymer could increase thermal stability and water resistance of the coatings and decrease their surface energy simultaneously. The observation of the fractured-surface morphology showed that the polysiloxanes could be well dispersed in the epoxy methacrylate to some extent. A suitable addition of such polysiloxane in photocurable coating matrixes may provide excellent properties for the cured coatings and widen their applications.     

Synthesis and characterization of side-chain liquid crystalline polysiloxanes

The synthesis and characterization are described for a series of side-chain liquid crystal polysiloxanes using polyhydrosilylation reaction between a poly(hydrogen methyl-co-dimethylsiloxanes),-(OSiHMe)_x,-(OSiMe2)_y-, where x/y was 13/87, 30/70, 55/45, 73/27 and 98/2, and [4-(allyloxy)benzoyll biphenyl mesogenic group. The side-chain liquid crystal polysiloxanes were characterized by¹H NMR,¹³C NMR, IR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and optical polarizing microscopy. The dimethylsiloxane segment factors governing thermal transition temperatures and activation energy (E_a) of the nematic-to-isotropic phase transition are discussed.     

Synthesis and characterization of polyacrylate modified by polysiloxane latexes and films

In this paper, a new method was designed to prepare polyacrylate modified by polysiloxane latex particles, with methyl methacrylate (MMA) and butyl acrylate (BA) as main monomers, vinyltriethoxysilane (A-151) as functional monomer and octamethylcyclotetrasiloxane (D₄) as grafting agent. The chemical structure and morphology of the latexes were characterized by FTIR, TEM, and particle size analyzer. The properties of the films were tested in terms of static contact angle, water absorption and TGA. The results showed that uniform spherical structure and narrow particle size distribution could be obtained in the latexes. Furthermore, the hydrophobicity, low surface free energy and thermal stability were also noticeably increased with the content of polysiloxane. The mechanism of ring opening polymerization between D₄ and A-151 was also discussed; it turned out that it was quite important to control the pH under faintly acid conditions.     

Synthesis and characterization of aromatic polyesters containing multiple n-alkyl side chains

A series of 2,2′-disubstituted-4,4′-dihydroxybiphenyl monomers was prepared from 3,4,5-tris(n-alkoxy)benzyl chlorides (n = 5, 6, 8, 10, 12) and tetramethylammonium salt of 4,4′-dihydroxydiphenic acid, which was synthesized from two different 5-step routes. 2,2′-Bis(trifluoromethyl)-4,4′-biphenyldicarboxylic acid was synthesized via 5-step route. A series of aromatic polyesters containing multiple alkyl side chains was prepared from the 2,2′-disubstituted-4,4′-dihydroxybiphenyl monomers and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldicarboxylic acid using diisopropylcarbodiimide as a dehydrating agent and 4-(dimethylamino)pyridinium 4-toluenesulfonate as a catalyst at room temperature. Their thermal and solution properties were measured and compared with the polyester without multiple alkyl side chains. The polyesters displayed better solubility in common solvents such as chlorinated solvents and THF but lower thermal stability than the polyester without multiple alkyl side chains. The intrinsic viscosities of the polyesters ranged from 0.68 to 2.53 dL/g and their number-average molecular weights ranged from 19,300 to 61,400. Polyesters containing C5–10 side chains were amorphous while the two polyesters containing C12 side chains crystallized at ?27 and ?31 °C, respectively. The thermal stability of the polyesters decreased as a result of alkyl side chains. The films of polyesters were opaque, indicating that the aromatic backbones and aliphatic side chains underwent phase separation.     

Synthesis, characterization, and thermal properties of poly(siloxane-carborane)s

Three exactly alternating carborane-siloxane polymers P1, P2, and P3, have been synthesized by the polycondensation of 1,7-bis(dimethylhydroxylsilyl)-m-carborane and cyclotrisilazanes in the presence of (NH₄)₂SO₄. The reaction shows a new and convenient synthesis of poly(carborane-siloxane)s, and the first example of stoichiometric polycondensation of cyclosilazanes with diols. The new polymers P2 and P3 could be converted into thermosets at elevated temperature through the cross-linking of pendant vinyl groups. The structures of the polymers were fully characterized. Thermogravimetric analysis (TGA) showed the superior thermal stability of the polymers and thermosets, with their char yields of over 83% both in air (800 °C) and nitrogen (1000 °C). The microstructure of the chars was studied by scanning electron microscopy (SEM). It was found that the cross-linking of vinyl groups helped in enhancing the thermal stabilities of the polymers and keeping the integrity of the chars. The results suggest their potential utility under severe thermal and/or thermo-oxidative conditions.     

含氰基联苯液晶基元侧链的聚酰胺的合成与表征

首先合成了一种含氰基联苯侧基的二胺单体,通过溶液缩聚合成了含氰基联苯液晶基元侧链的聚酰胺。用FTIR和1H NMR对中间体以及二胺单体的结构进行了详细的表征。DSC研究表明,聚酰胺表现出多重相转变行为,结合偏光显微镜的观察,结果表明,此聚酰胺呈现液晶性。进一步的WAXD研究又发现,聚酰胺在20℃附近区域出现多重衍射峰,同时在10℃以下的小角度区出现尖锐的衍射峰,说明形成了一种层状的液晶结构。     

The influence of lateral substituents on the phase behavior of side-chain liquid crystalline polysiloxanes containing trans-2,5-disubstituted-1,3-dioxane based mesogenic side groups

The synthesis and characterization of the polysiloxanes containingtrans-2,5-disubstituted-1,3-dioxane-based mesogenic side groups were described in this present study. Among three polysiloxanes containing three methylene units in their spacers, one without the lateral substituent exhibited two enantiotropic smectic phases while the other two polymers with a lateral methyl- or methoxy-substituent displayed an enantiotropic nematic phase. For polymers containing a longer spacer length (n 4), those without lateral substituent presented two enantiotropic smectic phases while the others containing a lateral substituent showed only an enantiotropic smectic A phase. The lateral substitution exerted a strong effect on the mesomorphic properties of the synthesized polymers.     

Synthesis of siloxanes containing reactive side chains

The synthesis and characterization of siloxanes containing methacrylate, epoxy, and amino side chains are described. Direct hydrosilylation of unsaturated methacrylate or epoxy compounds with methyl hydrogen siloxanes resulted in the attachment of methacrylate or epoxy groups as side chains on the siloxane in good yields. Amino side chains on siloxanes were formed by acidic hydrolysis of the ketenimine side chains, obtained by hydrosilylation of unsaturated ketenimines with methyl hydrogen siloxanes. Details of the preparation and characterization of such unsaturated ketenimines are reported.This paper is from the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.     

含短氟碳侧链及芳香环的甲基丙烯酰类单体的合成与表征

以全氟己基碘烷为原料通过一锅法制备了3-(全氟正己基)环氧丙烷,总收率达79.6%。从该环氧丙烷出发合成分离出了5种含短氟碳侧链及芳香环侧基的甲基丙烯酰类单体,并探讨了中间体含氟醇的最佳合成条件;通过1HNMR、13CNMR、19FNMR对合成单体进行了表征。     

Synthesis and characterization of novel polythiophenes containing poly(ethylene oxide) side chains

Thiophene copolymers and their derivatives with poly(ethylene oxide) side chains were synthesized. The starting monomers were 3‐hexylthiophene and 2‐(3‐thienyl) ethanol with poly(ethylene oxide) grafted to the side chains. New functionalized polythiophenes were prepared by both chemical oxidation with FeCl₃ and electropolymerization. The conjugating polymers were characterized. The structures of the polythiophene derivatives agreed with the design. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1803–1808, 2006     

2，1，5—磺酰氯合成的研究

结合国内原料来源情况,就光敏化合物2,1,5磺酰氯这一重要化工产品探索出适合我国国情的合成工艺路线,实验结果表明产品的质量、收率均接近国际水平。     

Synthesis of stretchable polyetherimides containing multiple alkyl side chains

Two series of diamine monomers, i.e., 4-[3,4,5-tris(n-alkan-1-yloxy)benzyl]-3,5-diaminobenzoate and 2,2′-bis{4-[3,4,5-tris(n-alkan-1-yloxy)benzoate]}-4,4′-biphenyldiamines containing multiple alkyl side chains, were synthesized in which the length of the alkyl side chains was varied from 5 to 18 ethylene units. Polyetherimides (PEIs) were prepared from these two diamines and bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydrides (BisADA) using a one-step method in 1-chloronaphthalene. All the polymers possessed good solubility in chlorinated solvents. The high-molecular weight PEIs could be solution cast into transparent, tough films. The polymers containing the side chains which were at least 16 methylene units could be crystallized. The melting points of the crystals increased as the length of the side chains increased. The glass transition temperatures (T_gs) of the PEIs decreased as the length of the side chains increased due to an internal plasticizing effect of the alkyl side chains. The PEIs containing multiple alkyl side chains showed excellent drawability with much higher elongations but lower tensile strengths and moduli compared with the commercial PEI, Ultem^® 1000. The film's in-plane refractive index parallel to the drawing direction (n_//) increased and its in-plane refractive index perpendicular to the drawing direction (n_⊥) decreased during drawing mainly due to the orientation of main chains in the drawing direction. The film's in-plane birefringence increased with the drawing ratios.     

Linear and hyperbranched liquid crystalline polysiloxanes

A series of liquid crystalline (LC) polymers having biphenyl (-C₆H₄C₆H₄R; R=H, OC₁₁H₂₃, OC(O)CH(Cl)CH₂CH₂COOCH₂CH₃) 4-methoxyphenyl benzoate (-C₆H₄C(O)OC₆H₄OCH₃) and cholesteryl type mesogenic moieties were synthesized. They were made from respective -Si(CH₃)₂H terminated mesogens and vinyl functionalized linear and star shape branched polysiloxanes of comb-like and dendritic topologies and were analyzed using WAXS and SAXS techniques. Contrary to the well defined typical dendrimers, in which mesogenic groups are present in an outer sphere, the dendritic systems described here contain such groups also inside the dendritic core. It was found that star shape and dendritic LC structures exhibited various calamitic mesophases (SmA, N* and SmC*) depending on the type of mesogenic groups. On the contrary, the comb-like structures give rise to formation of hexagonal phase, even though they contain typical rod-like mesogenic moieties. For the series of 4-methoxyphenyl benzoate substituted polymers the thorough studies of the relationship between their liquid crystalline properties and topology of siloxane skeleton was determined. Mechanical properties of the LC materials were also studied.     

Synthesis and characterization of N-phenylmaleimide-methylvinylisocyanate copolymers with polystyrene side chains

Summary N-Substitued maleimide-methylvinylisocyanate copolymers with high glass transition temperature (T_g) was prepared and reacted with 4-hydroxy TEMPO (4-hydroxy-2,2,6,6-tetramethyl piperidinoxy) to yield polymers possessing stable radical at the side chain. The resulting polymers behaved as polymeric counter radicals for the radical polymerization of styrene. Thus, stable free radical mediated polymerization at the side chain was achieved. The resulting graft copolymers were characterized by spectral and thermal analysis. Received: 6 October 1999/Revised version: 7 March 2000/Accepted: 7 March 2000     

Synthesis and surface mobility of segmented polyurethanes with fluorinated side chains attached to hard blocks

Novel polyurethanes with fluorinated side chains attached to hard blocks were synthesized and characterized by NMR, mass spectroscopy, DSC and gel permeation chromatography (GPC). A unique chain extender, 3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluoro-octyloxy)-propane-1,2-diol (PFOPDOL) was prepared from 3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluoro-octyloxymethyl)-oxirane (PDFOMO) by reacting it with diluted perchloric acid. Poly(ether urethane)s and poly(carbonate urethane)s containing various amounts of the chain extender with fluorinated side chains were then synthesized using methylenebis(phenylene isocyanate) (MDI), polytetramethyleneoxide (PTMO), poly(1,6-hexyl-1,5-pentylcarbonate) diol (PHPCD), 1,4-butandiol (BDO) and PFOPDOL. Mechanical properties of the polyurethanes were characterized by Instron. Surface properties were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Results from GPC and Instron studies indicated that fluorinated polyurethanes with high molecular weights and good mechanical properties were obtained. Results from XPS and contact angle studies indicated that the surface of fluorinated polyurethanes were very nonpolar due to migration of fluorinated side chains to the surface.     

Water and oil repellency of polysiloxanes with highly fluorinated alkyl side chains

A series of fluorinated polysiloxanes (FLSs) with the 3,3,4,4,5,5,6,6,6‐nonafluorohexyl group (C₄F₉C₂H₄? ), 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11‐heptadecafluoroundecyl group (C₈F₁₇C₃H₆? ), 3‐(2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9‐heptadecafluorononanamido) propyl group [HDFNAG; C₈F₁₇(C?O)NHC₃H₆? ], and 3‐(N‐methyl‐2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9‐heptadecafluorononanamido) propyl group [C₈F₁₇(C?O)N(CH₃)C₃H₆? ] were synthesized. Their homopolymers (homo‐FLSs) and copolymers with dimethylsiloxane (co‐FLSs) were included. The polyester fabrics were treated with these FLSs, and their water and oil repellency was evaluated. These fabrics showed a moderate to good level of water repellency but a poor to zero level of oil repellency, except for those fabrics treated with homo‐FLSs with HDFNAG. The characterization of the surface chemical composition by X‐ray photoelectron spectroscopy showed that the concentration of fluorine at the surface was not particularly high for poly(ethylene terephthalate) films treated with homo‐FLSs with HDFNAG. Differential scanning calorimetry measurements of these FLSs revealed that only homo‐FLSs with HDFNAG had a high melting temperature of 75.7°C. These two measurements suggested that the reason the fabrics treated with homo‐FLSs with HDFNAG showed good oil repellency was not because the concentration of fluorine at the surface was much higher than for the others but because the reorientation of HDFNAG did not take place for its packing after contact with oil. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1085–1091, 2003     

Synthesis of novel poly{methyl-[3-(9-indolyl)propyl]siloxane}-based nonlinear optical polymers via postfunctionalization

A novel series of nonlinear optical (NLO) polysiloxanes with a high density of chromophore moieties based on poly{methyl-[3-(9-indolyl)propyl]siloxane} (PMIPS) were synthesized by a post functional strategy. First, PMIPS (P1) was prepared through hydrosilylation reaction, then P1 is partially formylated by the reaction between P1 and the reagents of dimethylformamide (DMF) and phosphorus oxychloride under the standard Vilsmeier reaction conditions, and these formyl groups with high reactivity are condensed with four predesigned cyanoacetylated chromophores to afford the series of chromophore functionalized polysiloxanes (P3-6). The most special point is the molar concentrations of chromophore moieties are the same in polymers P3-6, which makes it convenient to study the behavior of different chromophores in the polymeric system. The poled films of P3-6 reveal the resonant d₃₃ values in the range of 7.9-55.2 pm/V by second harmonic generation (SHG) measurements.     

Synthesis and properties of epoxies containing rigid rods in the side chains

A novel epoxy containing rigid rods in the side chain (SR‐epoxy) was synthesized by bulk polymerization. The SR‐epoxy resins were characterized by Fourier transform infrared. The cured SR‐epoxies showed excellent mechanical properties and high thermal stabilities. Scanning electron microscopy (SEM) of the cured SR‐epoxy illustrated a fiber‐like morphology. The thermal properties, dynamic mechanical properties, compatibility, and morphology of the SR‐epoxies were extensively investigated in the study. SEM photographs showed that there were some fiber‐like structures in the system of the SR‐epoxy containing the rigid‐rod group 4,4′‐bis(6‐hydroxyhexoxy) biphenyl, which formed a self‐reinforcing composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4030–4036, 2006     

Synthesis and characterization of poly(lactide-b-siloxane-b-lactide) copolymers as magnetite nanoparticle dispersants

Poly(lactide-b-siloxane-b-lactide) triblock copolymers with pendent carboxylate groups have been synthesized to serve as dispersants for magnetite nanoparticles. Magnetic nanoparticles are of interest for potential biomedical applications including magnetic field-directed drug delivery and magnetic cell separations. For in-vivo applications, it is important that the magnetic particle be coated with biocompatible organic materials to afford dispersion characteristics or to further modify the surfaces of the complexes with biospecific moieties. Synthesis of the triblock copolymer dispersants comprises three reactions. First, difunctional, controlled molecular weight, telechelic, polymethylvinylsiloxane (PMVS) oligomers with 3-aminopropyl endgroups were prepared in ring-opening redistribution reactions. Secondly, these oligomers were utilized as macroinitiators for ring-opening l-lactide or d,l-lactide to provide triblock materials with PMVS central blocks and polylactide end blocks. Both the PMVS oligomers and the poly(lactide-b-siloxane-b-lactide) copolymers had the expected molecular weights and compositions. Thirdly, the vinyl groups on the polysiloxane center were functionalized with carboxylic acids by adding mercaptoacetic acid across the pendent double bonds. At neutral pH, the carboxylate-functional polysiloxane central block binds to the surfaces of magnetite nanoparticles, while the polylactides serve as tail blocks to provide dispersibility in polylactide solvents through interparticle steric repulsive forces. Analyses confirmed that the copolymers indeed adsorbed onto the surfaces of the magnetite nanoparticles, but fractionations of these materials suggested that the composition distribution of the components was somewhat inhomogeneous.     

Synthesis and properties of novel biodegradable polyurethanes containing fluorinated aliphatic side chains

This study used 5H–octafluoropentanoylfluoride and 2-amino-2-methyl-1,3-propanediol to synthesize a novel fluoro chain extender 2,2,3,3,4,4,5,5-octafluoro-N-(1,3-dihydroxy-2-methylpropan-2-yl) pentanamide (ODMP). Furthermore, 4,4′-diphenylmethane diisocyanate served as the hard segment, polycaprolactone diol (PCL) served as the soft segment, and ODMP served as the chain extender in the novel synthesized polyurethanes (ODMP/PUs). Gel permeation chromatography revealed that the molecular weight of the ODMP/PUs increased when the ODMP content was increased. ¹H and ¹⁹F nuclear magnetic resonance and Fourier transform infrared spectroscopy verified that the ODMP chain extenders were successfully synthesized and that the ODMP chain extenders were successfully incorporated into the backbone of the PUs. The interaction between the -NH (hydrogen bond) and CF₂ groups in the ODMP/PUs became stronger when the ODMP content was increased. Thermal analysis revealed that the initial decomposition temperature of the ODMP/PUs decreased and the second decomposition temperature increased when the polymers’ ODMP content was increased. Higher ODMP content also resulted in the ODMP/PUs’ higher glass transition and dynamic glass transition temperatures and lower ODMP maximum stress and Young’s modulus, causing a lower elongation at break. ODMP/PUs with higher ODMP content exhibited more protrusions and more rugged surfaces. The chemical resistance of the ODMP/PUs increased when the fluorine content was increased. Scanning electron microscopy revealed that ODMP/PUs with higher PCL content exhibited higher levels of hydrolytic degradation. Finally, in vitro erythrocyte tests revealed that increasing the ODMP chain extender content reduced the average number of erythrocytes adhering to the surface of the PUs.