Synthesis and properties of silicon-containing maleimide polymers based on N-(trimethylsilyl)maleimide

N-(Trimethylsilyl)maleimide (TMSMI) has been polymerized with various styrenic monomers (XSt) in the presence of a radical initiator to give high-molecular-weight, alternating copolymers in high yields. The copolymers P(TMSMI/XSt) have high glass transition temperatures above 200°C and thermal decomposition temperatures in the range 320–360°C. The thermal and acidolytic deprotection of trimethylsilyl (TMS) groups of TMSMI units in the copolymers have been investigated. UV irradiation and subsequent heating of a film of P(TMSMI/t-BOCSt) containing a photoacid generator resulted in deprotection of the protecting groups by the photogenerated acids, thereby causing a significant change in solubility of the polymer. Thus positive image patterns were obtained with P(TMSMI/t-BOCSt) by photolithographic processes. © 1998 Society of Chemical Industry     

Synthesis,characterization and properties of functionalized styrene–maleimide copolymers

New functionalized styrene–maleimide copolymers were prepared by free radical copolymerization of styrene (St) and N‐4‐carboxybutylmaleimide (NBMI) in chloroform, using 2,2′‐azobisisobutyronitrile (AIBN) as initiator. Monomer and copolymer characterization was carried out by ¹H‐ and ¹³C‐NMR. Copolymer composition was determined by elemental analysis and Fourier‐transform infrared (FTIR) spectroscopy. The glass transition temperature (from DSC) and the thermogravimetric analysis (TGA) of the copolymers were consistent with the thermal behavior and stability observed for alternating St–maleimide copolymers. St–NBMI copolymers crosslinked with divinylbenzene (DVB) were also synthesized and their cation exchange properties evaluated in order to assess the capacity of the new copolymers to bind metallic ions. Copyright © 2005 Society of Chemical Industry     

Copolymers of chosen alkyl methacrylates with N-phenylmaleimide and N-(4-halogenphenyl)maleimides: A UV-aging study

Homopolymers and copolymers of ethyl and butyl methacrylates with N-phenylmaleimide, N-(4-chlorophenyl)maleimide, and N-(4-bromophenyl)maleimide were synthesized by free-radical bulk polymerization with benzoyl peroxide as the initiator. The content of imide in the copolymers was about 5–10 or 7.5 wt %. The homopolymers and copolymers were irradiated with ultraviolet (UV) light in a climatic test chamber for various periods to study their aging behavior. After 100, 250, and 500 h, the structure, thermal stability, chemical resistance, and some physicomechanical properties were examined. The influence of UV radiation time on structure and the investigated properties of the homopolymers and copolymers were studied. The experimental results indicate that all investigated copolymers were resistant to UV radiation after 500 h. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3244–3250, 2001     

Copolymerization of N‐substituted maleimide with alkyl acrylate and its industrial applications

A series of new copolymers with desired thermal stability and mechanical properties for applications in leather industry were synthesized from various substituted maleimides and alkyl acrylates. Polymerization was carried out by a free‐radical polymerization using benzoyl peroxide (BPO) as initiator. The monomers and polymers synthesized were characterized by elemental analysis, IR, and nuclear magnetic resonance (NMR). Interestingly, these polymers were soluble in common organic solvents. Copolymer composition and reactivity ratios were determined by ¹H‐NMR spectra. The molecular weights of the polymers were determined by gel permeation chromatography. The homo‐ and copolymer of maleimide showed single‐stage decomposition (ranging from 300–580°C). The initial decomposition temperatures of poly[N‐(phenyl)maleimide] [poly(PM)], poly[N‐4‐(methylphenyl)maleimide] [poly(MPM)] and poly[N‐3‐(chlorophenyl)maleimide] [poly(CPM)] were higher compared to those of the copolymers. Heat‐resistant adhesives such as blends of epoxy resin with phenyl‐substituted maleimide‐co‐glycidyl methacrylate copolymers with improved adhesion property were developed. Different adhesive formulations of these copolymaleimides were prepared by curing with diethanolamine at two different temperatures (30°C and 60°C). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1870–1879, 2001     

Anionic polymerization and properties of graft copolymers consisting of alternating styrene/maleimide copolymer main chains and polyamide 6 grafts

This article is focused on the synthesis of a new type of graft PA6, which contained alternating styrene/maleimide copolymer main chains and PA6 grafts, by anionic polymerization. The preprepared styrene/maleimide copolymers with acylated caprolactam (ACL) pendants were used as macroactivators for the polymerization of molten ε‐caprolactam (CL). Because of the low activating energy for the initial nucleophilic attack of CL anion on the N‐ACL, the polymerization took place in a few minutes. The macroactivators were characterized by ¹H‐NMR. And the thermal properties, dimensional stability, crystallinity, and solvent resistance ability of the graft PA6 were studied, using DSC, TGA, XRD, water absorption measurement, and solubility experiment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of cyanato-functional polymaleimides and their application in negative-tone photoimaging by post-crosslinking

A cyanato-functional maleimide monomer (CyOPMI) was radically copolymerized with N-[4-(tetrahydropyranyloxy)phenyl]maleimide (THPPMI) and methyl methacrylate (MMA) to obtain reactive cyanate polymers along with acid-labile THP-protecting groups. The soluble copolymers of CyOPMI, employed as cyanato-imidopolymers, were converted to the insoluble polymers by thermal or photo-acid treatment based on the acid-catalyzed deprotection of THP groups and cyclotrimerization of the pendent cyanto groups to form a crosslinked triazine structure (cyanurate). Upon this selective post-crosslinking, the cyanato-polymers were applied to negative-tone photoimaging by photolithography. CyOPMI was radically copolymerized with various vinyl monomers such as MMA, styrenes (St) and alkyl vinyl ethers (R’VE) to obtain soluble polymers by controlling the monomer feed ratios and polymerization conditions. The high thermal properties of the cyanato-imido polymers were attributed to the curing characteristics of the pendant cyanatophenyl and imidophenolic groups.     

Synthesis and properties of silicon-containing polyamides

A series of aromatic polyamides incorporating silicon together with phenylquinoxaline or with hexafluoroisopropylidene groups has been synthesized by solution polycondensation of a silicon-containing diacid chloride with aromatic diamines having phenylquinoxaline rings or hexafluoroisopropylidene groups. These polymers are easily soluble in polar aprotic solvents, such as N-methylpyrrolidinone and dimethylformamide, and in tetrahydrofurane, and can be solution-cast into thin, transparent films having low dielectric constant, in the range of 3.26 to 3.68. These polymers show high thermal stability with decomposition temperature being above 400°C and glass transition temperature in the range of 236°C to 275°C. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1533–1538, 1997     

Controlled/living RAFT polymerization of N‐phenyl maleimide and synthesis of its block copolymers

The controlled/living radical polymerization of N‐phenyl maleimide (NPMI) was achieved using 2,2′‐azobisisobutyronitrile as the initiator and 2‐cyanopropyl‐2‐yl dithiobenzoate as the reversible addition‐fragmentation chain transfer agent at 75°C in dichloroethane/ethylene carbonate (60/40, w/w) mixed solvent. The block copolymers of polystyrene‐b‐polyNPMI and poly(n‐butyl methacrylate)‐b‐polyNPMI were successfully prepared by chain extension from dithiobenzoate‐terminated polystyrene and poly (n‐butyl methacrylate) to NPMI, respectively. The obtained NPMI‐based (co)polymers were characterized by gel permeation chromatography and ¹H‐NMR spectroscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

High-quality N-substituted maleimide for heat-resistant methacrylic resin

A preparation procedure for colorless, transparent N-substituted maleimide of high quality which can provide heat-resistant transparent methacryl resins was developed. N-Alkylmaleimide, the alkyl substituent of which was composed of 2 to 4 carbons, is employed, giving a polymer with enhanced heat distortion temperature (HDT) because of the higher T_g. The advantages of relatively low melting points and high vapor pressure of N-alkylmaleimide can be used for the preparation of a high-quality product with purification of the monomer by distillation. N-Isopropylmaleimide (IPMI), which fulfills these requirements, is especially useful as a monomer for transparent resins. IPMI was synthesized in a high-yield using a mixture of orthophosphoric acid and orthophosphoric acid-isopropylamine salt as catalyst. IPMI, the purity of which is 99.9 wt % or above, contains 100–200 ppm of N-isopropylmaleamic acid, maleic anhydride, dimethylmaleic anhydride, solvent, and water. IPMI, which solidifies at 25.8°C, is obtained as a colorless liquid and is freely soluble in common monomers such as methyl methacrylate (MMA), styrene (St), and acrylonitrile (AN). The obtained IPMI showed excellent thermal stability, and no quality change was observed after heating for 100 h at 50°C. The copolymer of MMA and IPMI exhibited the same YI value as a measure of coloration, and almost the same transparency as the homopolymer of MMA. An increase in IPMI content in the copolymer by 1 mol % increased the polymer T_g by 0.8°C. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1055–1062, 1997     

Nanoporous hard etch masks using silicon-containing block copolymer thin films

Nanoporous hard etch masks with various pore sizes were fabricated using a new type of silicon-containing block copolymers, polystyrene-block-poly(4-(tert-butyldimethylsilyl)oxystyrene) with different molecular weights. Since organic-inorganic block copolymers have a large difference in etch resistance between the organic and inorganic blocks, a hard etch mask of silicon oxide can be directly produced upon oxygen plasma treatment. Orientation and hexagonal arrays of cylindrical nanodomains were manipulated simply by adjusting the relative composition of selective and non-selective solvents in the annealing solvent. When the cylindrical nanostructures aligned perpendicular to the substrate surface were exposed to an oxygen plasma, hexagonally arranged nanopore arrays of silicon oxide with controlled pore sizes were fabricated. These nanoporous hard etch masks can be applied to the nanopatterning processes that require high aspect ratio structures.     

Sorption properties of polymers based on N‐substituted maleimides

Physicochemical and functional properties of 2,2‐diallyl‐1,1,3,3‐tetraethylguanidinium chloride copolymers with N‐(n‐carboxyphenyl)maleimide, of N‐vinylpyrrolidone with N‐(n‐carboxyphenyl)maleimide, and of N‐vinylpyrrolidone with N‐phenylmaleimide have been investigated. Specific surface area and porosity of the copolymers under investigation have been determined by using the low‐temperature adsorption method. Electron microscope investigations in surfaces of the polymers have evinced that all of them have a spongy microstructure, the N‐vinylpyrrolidone copolymer with N‐(n‐carboxyphenyl)maleimide being the most homogeneous of these. Sorption capacity of the copolymers toward Re(VII) ions has been investigated. The process is described by the Langmuir isotherm. The pH is the most important parameter for sorption process of Re(VII). In the conjoint presence of Re(VII) and Mo(VI) in a solution of acid and ammoniac mediums, rhenium can be separated from molybdenum by using the sorbents under investigation at pH > 4.5 or at hydrochloric acid concentrations 0.1 mol L^?1 and more. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of functional poly(acrylates and methacrylates) and block copolymers formation based on polystyrene macroinitiator by ATRP

The polymerization by ATRP of hydroxy and amino functional acrylates and methacrylates with tert-butyldimethylsilyl (TBDMS) or tert-butyloxycarbonyl (BOC) protective groups has been studied for the first time achieving high control over molecular weight and polydispersity. Detailed investigation of the ATRP of 2-{[tert-butyl(dimethyl)silyl]oxy}ethyl acrylate (M2b) in bulk and 2-[(tert-butoxycarbonyl)amino]ethyl 2-methylacrylate (M3a) in diphenyl ether (DPE) showed that the type of ligand plays an important role on either the polymerization rate or the degree of control of the polymerization. Among the ligands used, N,N,N,′N″N″-pentamethyl diethylenetriamine (PMDETA) was the most suitable ligand for ATRP of all functional acrylates and methacrylates. The kinetics of M2b and M3a polymerization using PMDETA as a ligand was reported and proved the living character of the polymerization. Well-defined block copolymers based on a halogen terminated polystyrene (Pst) macroinitiator and the functional acrylate and methacrylate monomers were successfully synthesized by ATRP, and subsequent deprotection of the protective groups from the acrylate or methacrylate segment afforded amphiphilic block copolymers with a specific solubility behavior.     

Synthesis and characterization of styrene–N-butyl maleimide copolymers using iniferters containing thiyl end groups

The radical homopolymerization of styrene or copolymerization of styrene (S) with N-butyl maleimide (I) initiated by tetraethylthiuram disulfide was used to prepare macroinitiators having thiyl end groups. The S–I copolymers from the feeds containing 30–70 mol % I showed approximately alternating composition. The rate of copolymerization and molecular weights decreased with increasing maleimide derivative concentration in the feed; homopolymerization of I alone did not proceed. The macroinitiators served for synthesis of further S–I copolymers. Using polystyrene macroinitiator and the S–I copolymer with thiyl end groups in the polymerization of S–I mixture and styrene, respectively, the copolymers containing blocks of both polystyrene and alternating S–I copolymer were obtained. The copolymerization of S–I mixture initiated with the S–I copolymer bearing thiyl end groups led to the extension of macroinitiator chains by the blocks of alternating copolymer. The presence of the blocks in the polymer products was corroborated using elemental analysis, size exclusion chromatography, and differential scanning calorimetry. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 755–762, 1998     

Synthesis and comparative study of thermal stabilities of the imidization of some maleic anhydride copolymers

In the present study, first, maleic anhydride‐styrene (MA‐St), maleic anhydride‐allyl phenyl ether (MA‐APhE), maleic anhydride‐heptene‐1(MA‐Hp), and maleic anhydride‐allyl propionate (MA‐AP) copolymers have been synthesized in different solvents in the presence of azobisisobutyronitrile (AIBN) at 70°C. Then, these four copolymers have been reacted with aniline at 60°C in N,N‐dimethyl formamide (DMF), and maleamidic acid derivatives of these copolymers have been synthesized. Next, they have been obtained from their maleimide derivatives by heating under vacuum at 150°C. All these polymers have been characterized by Fourier Transform infrared spectroscopy (FTIR) and investigated their thermal properties by using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) methods. The analyses results showed that thermal properties of maleimide derivatives of maleic anhydride copolymers changed as depend on the neighbor monomers of maleic anhydride. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2250–2254, 2006     

Synthesis and chain extension of nitroxide‐terminated styrene–maleimide copolymers

Thermal radical copolymerization of styrene (S) and maleimide (MI) at 125°C in diglyme in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl radical (TEMPO) was studied. Mole fractions of maleimide in the feed, F_MI, varied in the range 0.1–0.9. A quasiliving reaction process proceeded yielding copolymers with a low polydispersity (M_w/M_n = 1.17–1.41). The found azeotropic composition, (F_MI)_A = 0.46, did not differ substantially from that (0.5) in the conventional radical S‐MI copolymerization. At a higher conversion or MI content in the feed, deactivation of the copolymer chains occurred. The obtained TEMPO‐terminated S‐MI copolymers readily initiated polymerization of styrene; chain extension of the macroinitiators took place, giving poly(S‐co‐MI)‐block‐poly(S) diblock copolymers. The synthesized copolymers containing S and MI units were characterized by elemental analysis, NMR spectroscopy, size‐exclusion chromatography, and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1863–1868, 2004     

Homopolymerization and copolymerization of N‐substituted maleimides with chiral anionic initiators

Novel optically active anionic initiators bearing a chiral oxazole substituent on the fluorene ring, (S)‐1‐(9H‐fluoren‐2‐yl)‐4‐isopropyl‐4,5‐dihydrooxazole lithium (Li‐(S)‐1‐FIDH) and (S)‐2‐(9H‐fluoren‐2‐yl)‐4‐isopropyl‐4,5‐dihydrooxazole lithium (Li‐(S)‐2‐FIDH), were prepared. Anionic homopolymerizations of achiral N‐substituted maleimide (RMI) with the chiral initiators were investigated. The optically active polymers obtained were attributed to asymmetric induction of the chiral initiators. The very crowded chiral initiator Li‐(S)‐1‐FIDH was found to play a better asymmetric induction role in the polymers than Li‐(S)‐2‐FIDH. Anionic copolymerization of (R)‐(+)‐N‐1‐phenylethyl maleimide and optically inactive RMI with Li‐(S)‐1‐FIDH were also studied. © 2014 Society of Chemical Industry     

Synthesis and investigation of monomodal hydroxy-functionalized PEG methacrylate based copolymers with high polymerization degrees. Modification by “grafting from”

The synthesis of monomodal copolymers with poly(ethylene glycol) (PEG) side chains from commercial poly(ethylene glycol) methacrylates (PEGMA) by atom transfer radical polymerization (ATRP) is verified. Two hydroxy-functionalized PEGMA macromonomers (520 g/mol and 360 g/mol) were copolymerized with methyl methacrylate (MMA) using various initial feed (1.5/98.5–50/50 mol.%). The copolymers P(MMA-co-PEGMA) with high degree of polymerization, e.g. 100–275 of repeating units in the backbone including 7–56 PEG side chains, were obtained. The relative reactivity ratios of PEGMA and MMA determined by the Jaacks method indicated slightly faster incorporation of macromonomer into polymeric chain than MMA (r_MMA = 0.79; r_PEGMA = 1.27). The polymers containing at least 17 mol.% of PEGMA units were water-soluble and exhibited clouding point at temperature in a broad range of 39–70 °C. The temperature-sensitive effect makes these polymers as a potential carriers in drug delivery systems. In the case of copolymers insoluble in water, a three-step procedure, including esterification to ATRP multifunctional macroinitiators, ATRP of tert-butyl methacrylate (tBMA) by grafting from, deprotection of carboxylic groups by removing tert-butyl groups, was applied to extend PEG grafts and expand the content of hydrophilic fraction (32–94 mol.%), what efficiently developed polymer solubility in polar solvents giving possibility for the future biomedical applications.     

Effect of glass transition temperature on heat‐responsive gas bubbles formation from polymers containing tert‐butoxycarbonyl moiety

Various types of polymers containing tert‐butoxycarbonyl (BOC) moiety as the typical protecting group of functional moieties have been used for the design of stimuli‐responsive polymer materials. In this study, we investigated the heat‐responsive deprotection behavior of BOC‐containing polymers obtained by radical polymerization of 4‐(tert‐butoxycarbonyloxy)styrene (BSt) and copolymerizations of BSt with styrene and methyl acrylate. The deprotection of BOC groups accompanying the evolution of isobutene and carbon dioxide as gaseous products was monitored by thermogravimetric analyses at different temperature circumstances; that is, on heating at a rate of 10 °C/min and under isothermal conditions at various temperatures. The deprotection resulted in a significant decrease in the transmittance of visible light due to the formation of a large number of gas bubbles, that is, foaming, in the polymer films when a heating temperature was close to the glass transition temperature of the used polymer. The potential of BOC‐containing polymers was also evaluated as the heat‐responsive adhesive polymers for dismantlable adhesion. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46252.     

Synthesis of heat- and solvent-resistant polymers by radical polymerization of trifluoromethyl-substituted N-phenylmaleimides

The radical polymerization of the three kinds of fluorine-containing maleimides, that is, N-[2-(trifluoromethyl)phenyl]maleimide (2TFPhMI), N-[3-(trifluoromethyl)phenyl]maleimide (3TFPhMI), and N-[4-(trifluoromethyl)phenyl]maleimide (4TFPhMI) was carried out in the presence of a radical initiator in benzene at 60°C. The polymerization reactivity of these fluorine-containing maleimides and the properties of the resulting polymers were examined in comparison with the results for the methyl-substituted phenylmaleimides. The trifluoromethyl-substituted maleimides readily polymerized to give polymers in high yields as well as a methyl-substituted one. The resulting polymers showed an excellent resistance against organic solvents; especially, poly(4TFPhMI) was insoluble in the most common solvents. The onset temperature of thermal decomposition of the fluorine-containing polymers (T_init> = 352–368°C) was similar to that of poly(N-phenylmaleimide) (T_init = 364°C) and slightly lower than those for the methyl-substituted one (T_init = 388–402°C). The glass transition temperature of the polymers was dependent on the position of the trifluoromethyl group. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1703–1708, 1998     

Novel polymerizable N‐aromatic maleimides as free radical initiators for photopolymerization

Four kinds of polymerizable N‐aromatic maleimides (MIs)—4‐[(4‐maleimido)phenoxy]benzophenone (MPBP), 4,4′‐bis[(4‐maleimido)phenoxy]benzophenone (BMPBP), 4‐maleimidobenzophenone (MBP), and 4,4′‐bismaleimidobenzophenone (BMBP)—were synthesized as free radical photoinitiators, by introducing directly N‐phenylmaleimide groups or maleimide groups into the molecule of benzophenone (BP). Compared with BP, their UV‐visible spectra have a significantly red‐shifted maximum absorption. The maximum absorption of MIs containing bifunctional maleimide groups is slightly larger than the corresponding monofunctional ones. Choosing an unsaturated tertiary amine N,N‐dimethylaminoethyl methacrylate (DMAEMA) as coinitiator, the photopolymerization of 1,6‐hexanediol diacrylate (HDDA), initiated by these four MIs, was studied through photo‐DSC. The results show that all the MIs are dramatically more efficient than BP. Among them, MPBP is the most efficient, in which the polymerization rate is almost three times as high as that of the BP system. Photoinitiators containing bifunctional maleimide groups, though having higher final conversion, are less efficient than the corresponding monofunctional ones. These polymerizable photoredox systems significantly reduced the migration of the active species, leading to their higher efficiency. Copyright © 2006 Society of Chemical Industry