Preparation and film properties of tri(3,4-epoxycyclohexylmethyl) phosphate based cationically UV curing coatings

A facile synthesis of phosphorus-containing trifunctional cycloaliphatic epoxide resin, tri(3,4-epoxycyclohexylmethyl) phosphate (TECP), used for cationically UV curing coatings as a reactive-type flame retardant, was proposed. The molecular structure was confirmed by FTIR, ¹H NMR and ³¹P NMR spectroscopic analysis. A series of flame retardant formulations by incorporating into a commercial difunctional cycloaliphatic epoxide resin, CYRACURE™ UVR-6110, were prepared, and exposed to a medium pressure lamp to form the cured films under the presence of diaryliodonium hexafluorophosphate salt as a cationic photoinitiator. Their flame retardancy examined by the limiting oxygen index showed the improvement up to 27 for 50 wt% TECP addition compared with 21 for pure UVR-6110. The T_s and T_g decreased from 86 °C and 131 °C to 55 °C and 91 °C, respectively, by using dynamic mechanical thermal analysis, whereas the tensile strength showed a slight increase (11%) with 50 wt% TECP addition. The thermogravimetric analysis (TGA) and real-time Fourier transform infrared spectroscopy (RT-FTIR) measurement demonstrated the condensed-phase flame retardant mechanism.     

Synthesis of poly[(methyl methacrylate)-co-acrylamide] modified by titanium-triisopropoxide and their thermal stability

Poly[(methyl methacrylate)-co-acrylamide] of various compositions were previously prepared by the radical copolymerization reaction of methyl methacrylate and the acrylamide monomer in a solvent. The copolymers were modified through a resonating salt by the addition reaction of a chlorotitanium-triisopropoxide; the modified resins are called Ti hybrid copolymers. The chemical structure of acrylamide side chain groups in the Ti hybrid copolymers was confirmed by the ash weight after combustion, the characteristic absorption band determined by Fourier transform infrared spectrophotometry (IR) and elementary analysis (EA). The curing temperature and time of the resins were determined from the change in the insoluble resin weight when the extraction was done with a mixture of acetone and methanol using the curing resin samples. The thermal stability of the Ti hybrid copolymers was evaluated using both the thermal-degradation temperature (T_x) measured by thermogravimetric analysis and the thermal degradation at 130 °C for 720 h. The cured resins improved the weight loss of the resins at the T_x, and exhibited a high thermal stability.     

Flexible clear coats—Effect of curing conditions

The effect of curing at different conditions was investigated for flexible model clear coat films for coil coating applications. Based on a commercial polyester binder two formulations with isocyanate based crosslinking agents (hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI)) were prepared. The clear coats were baked at laboratory (145 °C) and industrial processing (300 °C) conditions. While for high temperature curing the baking time was kept constant at 30 s, the curing time at 145 °C, which is above the deblocking temperature of the crosslinking agents, was varied from 10 to 90 min. The clear coat films were characterized as to their thermomechanical and mechanical properties by dynamic mechanical analysis (DMA) and by tensile testing. Regarding DMA loading in tensile and penetration mode was performed.     

Bioengineering polyfunctional copolymers. VII. Synthesis and characterization of copolymers of p-vinylphenyl boronic acid with maleic and citraconic anhydrides and their self-assembled macrobranched supramolecular architectures

New boron-containing anion active functional copolymers are synthesized by complex-radical copolymerization of 4-vinylphenyl boronic acid and maleic or citraconic anhydrides with 2,2′-azobisisobutyronitrile as an initiator in DMF at 70 °C under nitrogen atmosphere. Macrobranched derivatives of these copolymers are synthesized by the partial grafting with α-hydroxy,ω-methoxy-poly(ethylene oxide) and incorporation with poly(ethylene imine). Effect of H-bonding on the formation of self-assembled supramolecular macrocomplexes with higher crystallinity and thermal stability was observed and confirmed by FTIR, and ¹H(¹³C DEPT-135( NMR spectroscopy, X-ray diffraction, DSC and TGA analyses of monomer, homopolymer, copolymer and grafted copolymer systems. Observed water solubility, biocompatibility and high density of acid groups in macromolecules allow these anion active B-containing copolymer systems for the developing new generation of effective antitumor agents, polymeric carriers for enzymes, gene delivery and boron neutron capture therapy.     

Synthesis and characterization of polyimides and co-polyimides having pendant benzoic acid moiety

A novel diamine monomer, 2,4-diamino-4′-carboxy diphenyl ether had been synthesized. Several polyimides were prepared by reacting this diamine with commercially available dianhydrides, such as benzophenone tetracarboxylic acid dianhydride (BTDA), 4,4′-bis{hexafluoroisopropylidene bis (phthalic anhydride)}(6-FDA), oxydiphthalic anhydride (ODPA) and 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA). Furthermore, copolymers from the resulting diamine and oxydianiline (ODA) with 6 FDA were also synthesized. The inherent viscosities of the polymers were 0.42-0.67 dl g⁻¹. The polymers have good solubility in polar aprotic solvents, high thermal stability up to 410 °C in nitrogen and high glass transition temperatures (T_g) ranging from 260-330 °C. These polymers formed tough flexible films by solution casting.     

Synthesis and characterization of novel polyimides derived from 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole with some of dianhydride monomers

A new kind of aromatic unsymmetrical diamine monomer containing thiazole ring, 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole (APPT), was synthesized. A series of novel polyimides were prepared by polycondensation of APPT with various aromatic dianhydrides via one-step process. The resulting polyimides held inherent viscosities of 0.40-0.71 dL/g and were easily dissolved in strong dipolar solvents. Meanwhile, strong and flexible polyimide films were obtained, which had thermal stability with the glass transition temperatures (T_g) of 268.2-328.8 °C in nitrogen, the temperature at 5% weight loss of 452-507 °C in nitrogen and 422-458 °C in air, and the residue at 800 °C of 54.18-63.33% in nitrogen, as well as exhibited outstanding mechanical properties with the tensile strengths of 105.4-125.3 MPa, elongations at breakage of 6-13%. These films also held dielectric constants of 3.01-3.18 (10 MHz) and showed predominantly amorphous revealed by wide-angle X-ray diffraction measurements.     

Novel carbazole phenoxy-based methacrylates to produce high-refractive index polymers

A novel, high-refractive index homopolymer was produced by incorporating carbazole and phenol into the methacrylate monomer structure. The reaction of phenol with 9-(2,3-epoxypropyl)-carbazole, followed by the reaction of the carbazole phenoxy-based intermediate with methacryloyl chloride or methacrylic anhydride, and recrystallization from methanol, produced a good yield of highly pure carbazole phenoxy functionalized methacrylate monomer. Subsequent free radical polymerization or UV photopolymerization of the functionalized methacrylate monomer, in addition to copolymerizations with methyl methacrylate, provided for high-refractive index materials well suited for lightweight optical applications. Unlike N-vinyl carbazole, the novel carbazole phenoxy-based methacrylate readily copolymerized with methyl methacrylate. Statistical copolymers of carbazole based methacrylates with methyl methacrylate were produced by free radical solution polymerization in DMAC or by photopolymerization in DMF. The carbazole phenoxy-based methacrylate monomer was characterized for molecular weight using gel permeation chromatography (GPC), for melting point and glass transition temperature using differential scanning calorimetry (DSC), for decomposition using thermal gravimetric analysis (TGA), and for chemical composition by one- and two-dimensional ¹H nuclear magnetic resonance (NMR) spectroscopy and by elemental analysis. The AIBN initiated carbazole phenoxy-based methacrylate polymerization was followed using in situ FTIR, which showed the reaction to be complete within 40 min in DMAC at 90 °C. Refractive indices of the carbazole based methacrylate homopolymers and copolymers ranged from 1.52 to 1.63. PhotoDSC was used to determine the heat of polymerization (ΔH_p) for the carbazole phenoxy-based methacrylate (ΔH_p=−39.4 kJ/mol). The carbazole phenoxy-based methacrylate homopolymer had a surprisingly high onset of decomposition temperature (T_onset=316 °C). ¹³C NMR spectroscopy experiments and molecular modeling were used to explore the configuration of the polymerized carbazole phenoxy-based methacrylate. The lack of head-to-head linkages due to steric considerations reasonably explains the high thermal stability observed for the carbazole phenoxy-based methacrylate polymer.     

Synthesis and properties of aliphatic spirodilactam diphenol containing polyesters

A series of aromatic polyesters containing 1,6-diazaspiro[4,4]-nonane-2,7-dione were synthesized under phase-transfer conditions. The copolymers were obtained in essentially quantitative yield, theses were soluble in common organic solvents, and would readily form clear, colorless films from solution. The optimum conditions of polymerization, was obtained via polycondensation at room temperature and reaction time of 4 h in chloroform. All polymers were characterized by FTIR, GPC, viscosity, water contact angle, water absorption, TGA, DSC and TMA. The prepared polyesters showed excellent thermal stability, as measured by TGA (10 wt% loss), are only moderate due to the alicyclic component and range from 365 to 401 °C in air; however, glass transition temperatures are quite high (245-309 °C). The inherent viscosities of these solutions ranged from 0.77 to 1.40 dl g⁻¹, depending on the polyester structure. The structures of the polyesters were confirmed by FTIR spectroscopy.     

Crosslinkable fully aromatic poly(aryl ether ketone)s bearing macrocycle of aryl ether ketone

A novel bisphenol monomer, (3-methoxy)phenylhydroquinone, was synthesized via a three-step synthetic procedure. The cyclization of the bisphenol monomer and 4,4-difluorobenzophenone was carried out under pseudo high dilution condition. Two types of fully aromatic poly(aryl ether ketone)s were prepared by copolymerization of macrocycle of aryl ether ketone (MACEK) containing hydroxyphenyl, 4,4′-(hexafluoroisopropylidene)diphenol (HFBPA), and 4,4-difluorobenzophenone. The copolymers have high molecular mass, good solubility and high glass transition temperatures. The copolymers are crosslinkable in the presence of basic initiator and the glass transition temperatures of the copolymers increased greatly after the curing. These cured copolymers exhibit excellent thermal stability, and the 5% weight loss temperatures are around 500 °C in nitrogen.     

Synthesis, characterization and photocross-linking of copolymers of furan and aliphatic hydroxyethylesters prepared by transesterification

Mild experimental conditions were applied to the synthesis of furan-aliphatic photoreactive copolymers by bulk transesterification, which called upon potassium carbonate as the catalyst, reaction times of about 30 h and temperatures ranging from 95 to 120 °C. The ensuing copolymers contained 3-10% of furan photoreactive monomer units, which absorbed at 308 nm, and had molecular weights of about 8000. They were semi-crystalline materials with glass transition temperatures of −51 to −62 °C and were stable up to 225 °C. The irradiation in the near-UV of concentrated solutions or thin films of these copolymers resulted in their cross-linking and suggested their possible use as photoresists, particularly in offset printing plates.     

A novel flame retardant UV‐curable vinyl ester resin monomer based on industrial dipentene: Preparation,characterization, and properties

A novel bio‐based and flame‐retardant UV‐curable vinyl ester resin (VER) monomer named Diglycidyl ester of maleinized dipentene modified with dibutyphosphate and methacrylic anhydride (MDDMD) was synthesized from industrial dipentene via Diels‐Alder reaction, glycidylation, epoxy ring‐opening reaction, and esterification. Its chemical structures were characterized by Fourier transform infrared (FTIR) analysis and proton nuclear magnetic resonance (¹H‐NMR). In order to improve its flexibility, we prepared a series of copolymers under UV light radiation by mixing it with certain proportions of poly(ethylene glycol) dimethacrylate‐200 (PEGDMA‐200) which contained flexible groups. Their tensile property, curing degrees (CD), hardness, limiting oxygen index (LOI), dynamic mechanical thermal properties, and thermostability were all investigated. The cured mixed resins have a relatively high tensile strength of 10.05 MPa and curing degrees up to 92.5%. Both hardness (range: 50 to 23 HD) and LOI (range: 22.8% to 24.4%) of cured resins are improved with the increase of MDDMD content. Dynamic mechanical analysis (DMA) shows that their glass transition temperatures rise with the increase of MDDMD content. Thermogravimetric analysis (TGA) shows that the thermal stability of cured resins is enhanced with the increase of PEGDMA‐200 content, as the main thermal initial decomposition temperatures are all above 260 °C and char yield at 800 °C are above 18.10%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44084.     

Synthesis and properties of novel organosoluble polyimides derived from 1,4-bis[4-(3,4-dicarboxylphenoxy)]triptycene dianhydride and various aromatic diamines

A novel triptycene-based dianhydride, 1,4-bis[4-(3,4-dicarboxylphenoxy)]triptycene dianhydride, was prepared from 4-nitro-N-methylphthalimide and potassium phenolate of 1,4-dihydroxytriptycene (1). The aromatic nucleophilic substitution reaction between 4-nitro-N-methylphthalimide and 1 afforded triptycene-based bis(N-methylphthalimide) (2), which hydrolyzed and subsequently dehydrated to give the corresponding dianhydride (3). A series of new polyimides containing triptycene moieties were prepared from the dianhydride monomer (3) and various diamines in m-cresol via conventional one-step polycondensation method. Most of the resulting polyimides were soluble in common organic solvents, such as chloroform, THF, DMAc and DMSO. The polyimides exhibited excellent thermal and thermo-oxidative stabilities with the onset decomposition temperature and 10% weight loss temperature ranging from 448 to 486 °C and 526 to 565 °C in nitrogen atmosphere, respectively. The glass transition temperatures of the polyimides were in the range of 221-296 °C. The polyimide films were found to be transparent, flexible, and tough. The films had tensile strengths, elongations at break, and tensile moduli in the ranges 95-118 MPa, 5.3-16.2%, and 1.03-1.38 GPa, respectively. Wide-angle X-ray diffraction measurements revealed that these polyimides were amorphous.     

In situ UV-vis spectroelectrochemistry of poly(o-phenylenediamine-co-m-toluidine)

Results of in situ UV-vis spectroelectrochemical studies of the electropolymerization of o-phenylenediamine (OPD), m-toluidine (MT) and the copolymerization of OPD with MT are reported. Electropolymerization was performed in aqueous acidic medium at a constant potential of E_SCE = 1.0 V at an indium doped tin oxide (ITO) coated glass electrode. The course of homopolymerization was followed for MT and OPD solutions with various monomer concentrations. The spectral characteristics of the mixed solutions were studied at a constant concentration of MT and various concentrations of OPD in the comonomer feed. An absorption band at λ = 497 nm was assigned to the head-to-tail mixed dimer/oligomer resulting from the cross reaction between OPD and MT cation radicals. UV-vis spectra recorded during copolymerization show dependence of the growth of the band at λ = 497 nm on OPD concentration in the feed. At lower OPD feed concentration it appears as the major band in the corresponding spectra. The UV-vis spectra recorded for the copolymer films suggest the incorporation of both monomer units in the copolymer. The FT-IR spectra of the copolymers show the presence of phenazine type structures in the copolymer backbone.     

Synthesis and characterization of low-birefringent crosslinkable fluorinated poly(arylene ether sulfide)s containing pendant phenyl moiety

Fluorinated poly(arylene ether sulfide) (FPAESI) and ethynyl-terminated fluorinated poly(arylene ether sulfide) (E-FPAESI) were synthesized via step-growth polymerization from prepared dihydroxy monomer and pentafluorophenylsulfide, then E-FPAESI was followed by a reaction with 3-ethynylphenol. The number-average molecular weights and polydispersities of FPAESI and E-FPAESI were in the range of 12,000-26,000 and 1.75-3.18, respectively. The glass transition temperatures of the polymers varied from 138 to 178 °C depending on the molecular weight of the polymer used and were changed to the range of 191-245 °C after curing. The FPAESIs and E-FPAESIs exhibited high thermal stability up to 445-450 °C and 457-462 °C, respectively. The refractive index and birefringence of spin-coated polymer films were determined by the prism-coupling method. The refractive indices and birefringences of the films were in the range of 1.5849-1.5880 and 0.0014-0.0035 at a 1550 nm wavelength, respectively. The effect of E-FPAESI structure on the birefringence is compared with various reported poly(arylene ether sulfide)s.     

Synthesis and properties of waterborne epoxy acrylate nanocomposite coating modified by MAP-POSS

In this paper, waterborne epoxy acrylate (EA) coating modified with methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) was prepared. The cure kinetics of the coating was investigated by differential scanning calorimetry (DSC). The curing process, thermal and mechanical properties of the coating were investigated by FTIR, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). These results show that the non-isothermal curing process can be described by Kissinger method and a two-parameter autocatalytic Šesták–Berggren (S–B) model. The kinetic equations of curing reaction were obtained. The UV-curing property of MAP-POSS/EA nanocomposite coating is better than that of pure epoxy acrylate system. The glass transition temperature (T_g) increases with increasing MAP-POSS content. When MAP-POSS content is 12 wt%, the T_g reaches the maximum 54.3 °C which is 9.5 °C higher than that of pure epoxy acrylate.     

Polyimides from 2,3,3′,4′-biphenyltetracarboxylic dianhydride and aromatic diamines

A series of new polyimides were prepared from the reaction of 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) with various aromatic diamines. The properties of the a-BPDA polyimides were compared with those of polyimides prepared from the reaction of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) with the same aromatic diamines. Films of the a-BPDA polyimides had higher glass transition temperatures (T_gs) and less color than the corresponding s-BPDA polyimide films. Light transmission at 500 nm, solar absorptivity, and thermal emissivity were determined on certain films. Films of similar polyimides based upon a-BPDA and s-BPDA containing meta linkages and others containing para linkages were each cured at 250, 300, and 350 °C. The films were characterized primarily by T_g, color, optical transparency, tensile properties, dynamic mechanical thermal analysis, and coefficient of thermal expansion. The a-BPDA meta linked polyimide films had tensile strengths and moduli higher than films of the a-BPDA para linked polyimide. The same phenomenon was not observed for the s-BPDA meta and para linked polyimides. The chemistry, mechanical, and physical properties of the polymers and films are discussed.     

Synthesis and characterization of new UV absorbing microspheres of narrow size distribution by dispersion polymerization of 2-(2′-hydroxy-5′-methacryloxyethylphenyl)-2H-benzotriazole

New UV absorbing microspheres of sizes ranging between 0.2 ± 0.03 and 3.0 ± 0.2 μm were formed by dispersion polymerization of the monomer 2-(2′-hydroxy-5′-methacryloxyethylphenyl)-2H-benzotriazole (trade name: NORBLOC) in methyl ethyl ketone as a continuous phase. The effect of various polymerization parameters, such as monomer concentration, initiator type and concentration, stabilizer concentration and crosslinker monomer concentration, on the size and size distribution, and on the polymerization yield of the produced PNORBLOC microspheres has been elucidated. Polyethylene/PNORBLOC resins and films of 150 ± 25 μm thickness were prepared by melt blending of low density polyethylene with 2% (w/w) PNORBLOC microspheres of 0.25 ± 0.03 μm diameters, followed by a tubular blown process at 170-190 °C. The UV irradiation (200-390 nm) cut-off efficiency of these films has been demonstrated.     

Formation of soluble hyperbranched polymer through the initiator-fragment incorporation radical copolymerization of ethylene glycol dimethacrylate with N-methylmethacrylamide

The copolymerization of ethylene glycol dimethacrylate (EGDMA) as a divinyl monomer with N-methylmethacrylamide (NMMAm) as a water-soluble monomer was carried out at 70 and 80 °C in N,N-dimethylformamide (DMF) using dimethyl 2,2′-azobisisobutyrate (MAIB) of high concentrations as initiator. When the concentrations of EGDMA, NMMAm and MAIB were 0.15, 0.50 and 0.35 mol/l, the copolymerization proceeded homogeneously with no gelation at 80 °C to give soluble copolymer in a yield of 50%. EGDMA was polymerized more rapidly than NMMAm as shown by Fourier-transform near infrared spectroscopy. The copolymer formed for 8 h consisted of 20 mol% of EGDMA unit, 47 mol% of NMMA unit and 33 mol% of methoxycarbonylpropyl group unit as MAIB-fragment. The copolymer formed at 80 °C for 30 min showed an upper critical solution temperature (34 °C on cooling) in methanol. The intrinsic viscosity of the copolymer formed for 2 h was very low (0.11 dl/g) at 30 °C in DMF despite high weight-average molecular weight [3.1×l0⁶ by multi-angle laser light scattering (MALLS)]. The copolymer exhibited a very low second virial coefficient (4.2×l0⁻⁶) as determined at 25 °C in DMF by MALLS. The individual copolymer molecules were observed as nanoparticles of 7-20 nm diameter by a transmission electron microscope. These results show that the resulting copolymers are of hyperbranched structure.     

Copolymerization of bis(chlorophthalimide)s with 2,5-dichlorobenzophenone catalyzed by NiBr2/PPh3/Zn

Copoly(phenylene-imide)s were synthesized by Ni(0)-catalyzed coupling of aromatic dichlorides containing imide structure and 2,5-dichlorobenzophenone. The route offered the flexibility of incorporating different ratios of benzophenone and imide groups in the polymer backbone in a controlled manner. The resulting copolymers exhibited high molecular weights (high inherent viscosity), and a combination of desirable properties such as good solubility in dipolar aprotic solvents and cresols, film-forming capability and good mechanical properties. Wide-angle X-ray diffractograms revealed that the polymers were amorphous. These copolymers had glass transition temperatures between 209 and 319 °C and 10% weight loss temperatures in the range of 502-543 °C in nitrogen atmosphere. The tough polymer films, obtained by casting from N-methylpyrrolidone solution, had a tensile strength range of 83-156 MPa and a tensile modulus range of 1.6-3.6 GPa.     

Dual-curing behavior and scratch characteristics of hydroxyl functionalized urethane methacrylate oligomer for automotive clearcoats

UV–thermal dual-curable, hydroxyl- and methacrylate-functionalized urethane oligomers with different contents of unsaturated double bonds and hydroxyl groups have been synthesized and incorporated into automotive clearcoats to investigate their curing and scratch behaviors. Dynamic mechanical analyses (DMA) and FT-IR analyses were performed to observe the variation of the crosslinking networks that resulted from the chemical reactions by UV and thermal dual-curing operations with varying curing conditions, such as UV dose, thermal curing time, thermal curing temperature, and curing sequence. The scratch behaviors of dual-cured automotive clearcoats were analyzed via nano-scratch tests, accompanied with scratch images simultaneously visualized using scanning electron microscopy (SEM). The mechanical and chemical properties, such as impact resistance, pencil hardness, acid-etch resistance, and stone-chip resistance, of dual-curable clearcoats were also compared with those of UV mono-cure and 1 K thermal-cure clearcoats. The results clearly showed that the dual-curing process induced a considerably higher degree of crosslinking for the cured clearcoats prepared from the dual-curable oligomers, melamine crosslinkers, and photoinitiators. Their mechanical properties including scratch resistance were also noticeably improved via the UV–thermal curing sequence, which led to an increased conversion rate of double bonds compared with clearcoats produced using the thermal–UV curing sequence. The best conditions for high crosslinking density as well as high hardness and modulus were 2400 mJ/cm² at 150 °C for 10 min in the UV–thermal curing process. This result was corroborated from the reaction kinetics and surface images of the scratched clearcoats captured by SEM.