Block copolymers of cyclohexene oxide and ketonic resins via condensation and promoted cationic polymerization

Block copolymers of cyclohexene oxide (CHO) and ketonic resin were prepared by using ketonic resins as free radical photoinitiators via two‐step procedure. In the first step, cyclohexanone–formaldehyde and acetophenone–formaldehyde resins were modified during their preparation with benzoin and benzoin isobutyl ether. Then, AB or ABA type block copolymers depending on the resin employed were obtained by irradiation of these resins in the presence of pyridinium salt and CHO as a cationically polymerizable monomer. By this way, block copolymers of CHO with ketonic resin were prepared and characterized by GPC, DCS, FTIR, and ¹H NMR spectral measurements. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Ketonic resins as free radical photoinitiators

Photoreactive cyclohexanone‐formaldehyde and acetophenone‐formaldehyde resin‐bound benzoin and benzoin isobutyl ether resins were successfully prepared by the method of in situ modification of ketonic resins. These photoinitiators were used to polymerize styrene using UV lamp with wavelength of 350 nm. Initiating efficiencies of ketonic resin‐bound benzoin and benzoin ether were much higher than benzoin and benzoin ether. The products were ketonic‐resin‐polystyrene block copolymers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 927–934, 1999     

In situ preparation of cyclohexanone formaldehyde resin/layered silicate nanocomposites

In this study, in situ modified cyclohexanone formaldehyde resin (CFR) was prepared from clay (montmorillonite) and polydimethylsiloxane with diamine chain ends [α,ω‐diamine poly(dimethyl siloxane) (DA.PDMS)] in the presence of a base catalyst. Different clay contents (from 0.5 to 3 wt %) were used to produce clay‐modified nanocomposite ketonic resins [layered clay (LC)–CFR] and clay‐ and DA.PDMS‐modified nanocomposite ketonic resins (DA.PDMS–LC–CFR). The polymeric nanocomposite material prepared by this method was directly synthesized in one step. These nanocomposites were confirmed from X‐ray diffraction to have a layered structure with a folded or penetrated CFR, and they were further characterized via Fourier transform infrared spectroscopy–attenuated total reflectance and NMR spectroscopy. The thermal properties of all of the resins were studied with differential scanning calorimetry and thermogravimetric analysis. All of the resins showed higher thermal stability than their precursor CFR resin. The obtained samples were also characterized morphologically by scanning electron microscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39918.     

Styrene polymerization with a macroinitiator having siloxane units

Block copolymers containing segments of poly(dimethylsiloxane) (PDMS) and polystyrene were synthesized. Dihydroxy terminated PDMS M_n 2500 g/mol, was reacted with an ali-phatic diisocyanate (isophorone diisocyanate) and an aliphatic hydroperxide (t-butyl hy-droperoxide). The resulting polymeric peroxycarbamate having siloxane units (a new mac-roinitiator) was used as free radical initiator for vinyl polymerization of styrene. Formation of block copolymers was illustrated by several characterization methods such as chemical and spectroscopic analysis, fractionation, and GPC. Mechanical and thermal characterization of the copolymers were made by stress–strain tests and DSC. The surface properties and the morphology of the block copolymers were investigated by contact angle measurements and SEM. © 1996 John Wiley & Sons, Inc.     

Some structure-property relationships in polymer flammability: Studies of phenolic-derived polymers

The investigation of the thermal degradation of the char-formaing phenol–formaldehyde resins is conducted to provide information for the systematic design of high temperature flame-resistant phenolics. Three different processes of curing are used: (1) Formaldehyde or s-trioxane is reacted with m-substituted phenol–formaldehyde oligomers under acidic conditions to give the methylene bridged-novolac resins. (2) Phenol and m-substituted phenols are reacted with CH₂O under basic conditions and then heated to give the methylene bridged resol resins. (3) p-Terephthaloyl chloride and m-and p-substituted novolac oligomers are reacted to give cured resins with ester linkages. The evaluation of the effect of various substituents indicates that the oxygen index (OI) increases from about 33 for unsubstituted phenolics to about 75 for meta-halogen substituted phenolics. The evaluation of the effect of various crosslinking agents shows that the OI for CH₂O-cured phenolics is 75 as compared to 50 for the trioxane cured phenolics and to 40 for the terephthaloyl chloride cured phenolics. A set of phenolic copolymers with different weight percentage content of halogen substituted phenols are synthesized as novolacs and resols. The results surprisingly indicate no increase of OI for the cured novolac copolymers, whereas the increase is observed for the cured resol copolymers. The activation energy for the thermooxidative degradation of the cured novolacs is about 12–15 kJ/mol lower as compared to that of the curd resols.     

Polypyrrole–vinyl aniline modified cyclohexanone formaldehyde resin copolymers: a comparative study of the resin preparation

In this study, the synthesis of polypyrrole‐b‐vinyl aniline modified cyclohexanone formaldehyde resin (PPy‐b‐CFVAnR) block copolymers by a combination of condensation polymerization and chemical oxidative polymerization processes was examined. First, a cyclohexanone formaldehyde resin containing vinyl aniline units [4‐ vinyl aniline modified cycl?ohexanone formaldehyde resin (CFVAnR)] was prepared by a direct condensation reaction of 4‐vinyl aniline and cyclohexanone with formaldehyde in an in situ modification reaction. CFVAnR and pyrrole (Py) were then used with a conventional method of in situ chemical oxidative polymerization. The reactions were carried out with heat‐activated potassium persulfate salt in the presence of p‐toluene sulfonic acid in a dimethyl sulfoxide–water binary solvent system; this led to the formation of desired block copolymers. The effects of the oxidant–monomer molar ratio, dopant existence, addition order of the reactants, and reaction temperature on the yield, conductivity, and morphology of the resulting products were investigated. PPy‐b‐CFVAnR copolymers prepared with a resin‐to‐Py molar ratio of 1:40 showed conductivity in the range 3.7 × 10^?1 to 3.8 × 10^?2 S/cm. Oxidant‐to‐Py molar ratios of 0.5 and 1.0 were proposed to be the optimum stoichiometries for higher conductivity and yield, respectively, of the copolymer. The morphology of the copolymer (PPy‐b‐CFVAnR) was investigated with environmental scanning electron microscopy analyses. The results indicate that the surface of the copolymer was composed of well‐distributed nanospheres with average particle diameters of 60–85 nm. Also, the synthesized PPy‐b‐CFVAnR had a higher thermal stability than the pure CFVAnR. The chemical composition and structure of the PPy‐b‐CFVAnR copolymers were characterized by Fourier transform infrared spectroscopy and measurement. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42841.     

Rheo-optical Fourier transform near-infrared spectroscopy of polydimethylsiloxane/polycarbonate block copolymers

A series of polydimethylsiloxane (PDMS)/polycarbonate (PC) block copolymers with varying compositions were investigated by simultaneous mechanical and Fourier transform near-infrared (FTNIR) spectroscopic (rheo-optical) measurements to study segmental orientation during elongation-to-break and cyclic elongation–recovery procedures. Depending on the composition and the block lengths of the copolymers, different orientational and recovery phenomena were observed for the hard (PC) and soft (PDMS) segments. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1349–1357, 1998     

Chain extended cyclohexanone-formaldehyde and acetophenone–formaldehyde resins

The preparation of chain extended cyclohexanone–formaldehyde and acetophenone–formaldehyde resins and their physical properties were studied. The chain extension was regulated by the ratio of the hydroxyl groups of the ketonic resin/reactive reagents. Both resins were chain extended with dimethyl dichlorosilane, phosphorus oxychloride, phenylphosphonic dichloride, toluene-2,4-diisocyanate, prepolymers (prepared from trimethylolpropane and toluene-2,4-diisocyanate), phthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride, and maleic anhydride. Solubilities, melting point, molecular weight, and flammability of the chain extended resins were affected by the extender reagent. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 655–663, 1998     

Synthesis and properties of multiblock copolymers based on polydimethylsiloxane and piperazine-aromatic polyamides

Polydimethylsiloxane (PDMS)–polyamide multiblock copolymers were synthesized by three different methods, i.e., two-step low-temperature solution polycondensation, one-step solution polycondensation, and interfacial polycondensation. In the two-step method, α,ω-diacid chlorideterminated polyamide oligomers were prepared from trans-2,5-dimethylpiperazine (DMP) and terepthaloyl chloride (TPC) or isophthaloyl chloride (IPC) in chloroform in the presence of triethylamine, which in turn were subjected to reaction with α,ω-bis (3-aminopropyl) polydimethylsiloxane (PDMS–diamine) in the same solvent to from multiblock copolymers. In the one-step method, the reaction components, DMP, TPC (or IPC), and PDMS–diamine, were reacted altogether in chloroform in the presence of triethylamine. In the interfacial method, the reaction components were also reacted altogether in an aqueous sodium hydroxide–chloroform two-phase system. These polycondensations afforded the multiblock copolymers having inherent viscosities of 0.1–1.3 dL g^?1 in m-cresol. The PDMS–polyamide multiblock copolymers dissolved in formic acid and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), and transparent, ductile, and elastomeric films were obtained by casting from the HFIP solutions. The films of the multiblock copolymers prepared by three different methods exhibited similar properties by means of thermal analysis and tensile measurements. In the multiblock copolymers, the tensile strength and modulus of the films decreased with increasing the PDMS content, whereas the elongation at break increased.     

Poly(hydroxyether of bisphenol A) ‐alt‐polydimethylsiloxane: a novel thermally crosslinkable alternating block copolymer

BACKGROUND: An important strategy for making polymer materials with combined properties is to prepare block copolymers consisting of well‐defined blocks via facile approaches. RESULTS: Poly(hydroxyether of bisphenol A)‐block‐polydimethylsiloxane alternating block copolymers (PH‐alt‐PDMS) were synthesized via Mannich polycondensation involving phenolic hydroxyl‐terminated poly(hydroxyether of bisphenol A), diaminopropyl‐terminated polydimethylsiloxane and formaldehyde. The polymerization was carried out via the formation of benzoxazine ring linkages between poly(hydroxyether of bisphenol A) and polydimethylsiloxane blocks. Differential scanning calorimetry and small‐angle X‐ray scattering show that the alternating block copolymers are microphase‐separated. Compared to poly(hydroxyether of bisphenol A), the copolymers displayed enhanced surface hydrophobicity (dewettability). In addition, subsequent crosslinking can occur upon heating the copolymers to elevated temperatures owing to the existence of benzoxazine linkages in the microdomains of hard segments. CONCLUSION: PH‐alt‐PDMS alternating block copolymers were successfully obtained. The subsequent self‐crosslinking of the PH‐alt‐PDMS alternating block copolymers could lead to these polymer materials having potential applications. Copyright © 2008 Society of Chemical Industry     

Synthesis of block copolymers from PDMS macroinitiators

The synthesis of polystyrene‐b‐polydimethylsiloxane‐b‐polystyrene (PSt‐b‐PDMS‐b‐PSt) copolymers is described. Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide resulting in the PDMS macroinitiators. The terminal alkyl bromide groups were then used as initiators for atom transfer radical polymerization (ATRP) to produce block copolymers. Using this technique, triblock copolymers consisting of a PDMS centre block and polystyrene terminal blocks were synthesized. ATRP of St from those macroinitiators showed linear increases in M_n with conversion, demonstrating the effectiveness of ATRP to synthesize a variety of inorganic/organic polymer hybrids. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of Pst‐b‐PDMS‐b‐PSt copolymers by atom transfer radical polymerization

Polystyrene‐b‐poly(dimethylsiloxane)‐b‐polystyrene (Pst‐b‐PDMS‐b‐PSt) triblock copolymers were synthesized by atom transfer radical polymerization (ATRP). Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide, resulting in the PDMS macroinitiators for the ATRP of styrene (St). The latter procedure was carried out at 130°C in a phenyl ether solution with CuCl and 4, 4′‐di (5‐nonyl)‐2,2′‐bipyridine (dNbpy) as the catalyzing system. By using this technique, triblock copolymers consisting of a PDMS center block and polystyrene terminal blocks were synthesized. The polymerization was controllable; ATRP of St from those macroinitiators showed linear increases in M_n with conversion. The block copolymers were characterized with IR and ¹H‐NMR. The effects of molecular weight of macroinitiators, macroinitiator concentration, catalyst concentration, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3764–3770, 2004     

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     

Chemical polymerization of pyrrole in the presence of ketone–formaldehyde resins

The chemical polymerizations of pyrrole in the presence of acetophenone and formaldehyde, cyclohexanone, acetaldehyde, and formaldehyde, cyclohexanone and formaldehyde, cyclohexanone, resorcinol, and formaldehyde, cyclohexanone and lignosulfonate formaldehyde, and cyclohexanone, pyrrole, and formaldehyde were accomplished with Ce(IV) salt in acetonitrile solutions. The roles of the resin type, the addition order of the reactants, and the concentrations of the pyrrole and resin on the solubility and conductivity of the resulting products were investigated. The cyclohexanone–acetaldehyde–formaldehyde resin/polypyrrole copolymer had the highest solubility in dimethylformamide. The conductivity and solubility of the copolymers could be controlled by the Ce(IV)/pyrrole/resin molar ratio. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 618–624, 2005     

Preparation and characterization of block and graft copolymers using macroazoinitiators having siloxane units

α,ω-Amine terminated organofunctional polydimethylsiloxane (PDMS) was condensed with 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) to prepare macroazoinitiators containing siloxane units. Interfacial polycondensation reaction at room temperature was applied: ACPC was slightly dissolved in carbon tetrachloride and it was poured on aqueous NaOH solution of PDMS. Block copolymers containing PDMS as a block segment combined with polystyrene (PS) have been derived by the polymerization of styrene monomer initiated by these macroazoinitiators. PS-b-PDMS block copolymers were characterized by using nuclear magnetic resonance and infrared spectroscopy. Thermal and mechanical properties of the block copolymers were studied by using thermogravimetric analysis, differential scanning calorimetry, and a Tensilon stress-strain instrument. The morphology of block copolymers was investigated by scanning electron microscopy. PDMS-g-polybutadiene (PBd) graft copolymers were also prepared by reaction of PBd with the above macroazo-initiator. Increase in the amount of macroazoinitiator in the mixture of PBd (52% w/w) leads to the formation of crosslinked graft copolymers. Molecular weights of soluble graft copolymer samples were between 450 and 600 K with a polydispersity of 2.0–2.3. © 1996 John Wiley & Sons, Inc.     

Synthesis of cyclohexanone formaldehyde resin‐methylmethacrylate block‐graft copolymers via ATRP

Well defined block‐graft copolymers of cyclohexanone‐formaldehyde resin (CFR) and methylmethacrylate (MMA) were prepared via atom transfer radical polymerization (ATRP). In the first step, cyclohexanone formaldehyde resin (CFR) containing hydroxyl groups were modified with 2‐bromopropionyl bromide. Resulting multifunctional macroinitiator was used in the ATRP of MMA using copper bromide (CuBr) and N,N,N′,N″,N″‐pentamethyl‐diethylenetriamine (PMDETA) as catalyst system at 90°C. The chemical composition and structure of the copolymers were characterized by nuclear magnetic resonance (¹H‐NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and molecular weight measurement. Molecular weight distributions of the CFR graft copolymers were measured by gel permeation chromatography (GPC). M_n values up to 19,000 associated with narrow molecular weight distributions (polydispersity index (PDI) < 1.6) were obtained with conversions up to 49%. Coating properties of synthesized graft copolymers such as adhesion and gloss values were measured. They exhibited good adhesion properties on Plexiglas substrate. The thermal behaviors of all polymers were conducted using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of semi‐crystalline poly(ε‐caprolactone) and non‐crystalline polylactide blocks on the thermal properties of polydimethylsiloxane‐based block copolymers

Poly(A)‐block‐poly(B), poly(A)‐block‐poly(B)‐block‐poly(A) and B(A)₂ block copolymers were prepared through coordinated anionic ring‐opening polymerization of ε‐caprolactone (CL) and lactic acid (LA) using hydroxy‐terminated polydimethylsiloxane (PDMS) as initiator. A wide range of well‐defined combinations of PDMS‐block‐PCL and PDMS‐block‐PLA diblock copolymers, PCL‐block‐PDMS‐block‐PCL and PLA‐block‐PDMS‐block‐PLA triblock copolymers and star‐PDMS(PCL)₂ copolymers were thus obtained. The number‐average molar masses and the structure of the synthesized block copolymers were identified using various analytical techniques. The thermal properties of these copolymers were established using differential scanning calorimetry. Considering PDMS‐block‐PCL copolymers, the results demonstrate the complex effect of polymer architecture and PCL block length on the ability of the PDMS block to crystallize or not. In the case of diblock copolymers, crystallization of PCL blocks originated from stacking of adjacent chains inducing the extension of the PDMS block that can easily crystallize. In the case of star copolymers, the same tendency as in triblock copolymers is observed, showing a limited crystallization of PDMS when the length of the PCL block increases. In the case of PDMS‐block‐PLA copolymers, melting and crystallization transitions of the PLA block are never observed. Considering the diblock copolymers, PDMS sequences have the ability to crystallize. © 2019 Society of Chemical Industry     

Block copolymers derived from azobiscyanopentanoic acid. XI. Properties of silicone–PMMA block copolymers prepared via polysiloxane(azobiscyanopentanamide)s

Mechanical, thermal, and surface properties of poly(dimethylsiloxane)–poly(methyl methacrylate) block copolymers (PDMS-b-PMMA) prepared by the use of polysiloxane(azobiscyanopentanamide)s were intensively investigated. The mechanical strength of block copolymers was found to decrease with an increase of siloxane contents. Dynamic mechanical analysis (DMA) of block copolymers having long siloxane chain length (SCL) and high siloxane content revealed the existence of two glass transitions attributable to microphase separation of two segments. Differential scanning calorimetry (DSC) also gave some evidence of microphase separation supporting the DMA results. It was observed that the incorporation of PDMS segments in block copolymers improved thermal stability of PMMA, as confirmed by thermogravimetric analysis. Surface analysis of the block copolymers films cast from several solutions indicated surface accumulation of PDMS segments, as revealed by water contact angle and ESCA measurements.     

New melamine–formaldehyde–ketone resins. VI. Preparation of filled molding compositions and compression‐molding materials from reactive solvents based on cyclohexanone

The conditions and a method of preparing new molding compositions and filled compression‐molding materials from melamine–formaldehyde–cyclohexanone resins are described. The resins were obtained from melamine solutions in a reactive solvent prepared by the reaction of 1 mol of cyclohexanone with 7 mol of formaldehyde. The fillers were wood powder and sulfite cellulose. The thermal properties of the samples prepared from the compositions were studied with dynamic thermal analysis, thermogravimetry, and differential scanning calorimetry analysis. Selected mechanical properties [Brinell hardness, unnotched impact strength (Charpy method), and bending strength] of the cured resins were also measured. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Flame retardancy of a polycarbonate–polydimethylsiloxane block copolymer: The effect of the dimethylsiloxane block size

This report describes the flame retardancy of a polycarbonate (PC)–polydimethylsiloxane (PDMS) block copolymer with a dimethylsiloxane (DMS) block size of 15–350 units, and the effects of the block size and amount of DMS on the flame retardancy are studied. PC–PDMS block copolymers with DMS units of 40–130 had high limiting oxygen index values with 1.0 wt % PDMS. The PDMS block size influenced the PDMS dispersibility in PC, and a moderate PDMS dispersion (ca. 50 nm) caused high flame retardancy for PC. These PC–PDMS block copolymers could form a lot of fine bubbles in the role of good thermal insulators through the reaction of PC and PDMS in combustion. Furthermore, the silica particles from PDMS remained mostly on the surface of the char, so the amount of char with high oxidation resistance increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 565–575, 2006