Copolymers of higher alkyl methacrylates with triallyl cyanurate

Copolymers of higher methacrylates (propyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, and dodecyl) with triallyl cyanurate were synthesized by free-radical polymerization using benzoyl peroxide as initiator. The properties of the copolymers such as thermal stability, T_g, Vicat softening temperature, hardness, refractive indices n_D, chemical stability, density, and shrinkage on polymerization were studied. The influence of the alcohol alkyl chain length in methacrylates and the content triallyl cyanurate in copolymers on their properties is discussed. © 1995 John Wiley & Sons, Inc.     

Physicochemical properties of irradiated and loaded LDPE films with polyfunctional monomers

Polyfunctional monomers (PFMs), namely, trimethylol propane trimethacrylate (TMPTMA), trimethylol propane triacrylate, ethylene glycol dimethacrylate, and diethylene glycol diacrylate were blended with low‐density polyethylene (LDPE) and exposed to different doses of EB irradiation. Fourier transform infrared and ultraviolet and UV–vis spectroscopy of the unirradiated, irradiated, unloaded, and PFMs‐loaded LDPE films were studied under various irradiation doses up to 300 kGy. The degree of crosslinking and oxidative degradation, as measured by the spectroscopic parameters, were dependent on both the irradiation dose and the type of loaded PFMs. For all of the loaded monomers, the extent of crosslinking increased at different rates as a function of irradiation dose. TMPTMA monomer was the most efficient in enhancing the crosslinking of LDPE films compared to the other loaded monomers. However, the unloaded LDPE film showed the least extent of crosslinking. In addition, the EB‐radiation‐induced changes, such as trans‐vinylene formation, a decrease in vinyl and vinylidene unsaturation; and carbonyl double‐bond formation and change in crystallinity were correlated. The importance of these results on the prediction of the role of polyfunctional monomers in the production of crosslinked polymers is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2025–2035, 2003     

Multifunctional peroxide as alternative crosslink agents for dynamically vulcanized epoxidized natural rubber/polypropylene blends

Commonly used dicumyl peroxide (DCP) in combination with coagent, triallyl cyanurate (TAC), as a crosslinking agent is well acceptable for dynamically vulcanized rubber phase of thermoplastic vulcanizates (TPVs). However, it generally produces volatile decomposition products, which cause a typical unpleasant smell and a blooming phenomenon. In this work, influence of two types of multifunctional peroxides: 2,4‐diallyloxy‐6‐tert‐butylperoxy‐1,3,5‐triazine (DTBT) and 1‐(2‐tert‐butylperoxyisopropyl)‐3‐isopropenyl benzene (TBIB), on properties of TPVs based on epoxidized natural rubber (ENR)/polypropylene (PP) blends were investigated. The conventional peroxide/coagent combinations, i.e., DCP/TAC and tert‐butyl cumyl peroxide (TBCP)/α‐methyl styrene (α‐MeS) were also used to prepare the TPVs for a comparison purpose. The TPVs with multifunctional peroxide, DTBT, provided good mechanical properties and phase morphology of small dispersed vulcanized rubber domains in the PP matrix which were comparable with the DCP/TAC cured TPVs. However, the TPVs with TBIB/α‐MeS and TBCP/α‐MeS showed comparatively low values of the tensile properties as well as rather large phase morphology. The results were interpreted by three main factors: the kinetic aspects of the various peroxides, solubility parameters of respective peroxide/coagent combinations in the ENR and PP phases, and the tendency to form unpleasantly smelling byproducts. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Efforts to decrease crosslinking extent of polyethylene in a reactive extrusion grafting process

Grafting of acrylic acid and glycidyl methacrylate onto low density polyethylene (LDPE) was performed by using a corotating twin‐screw extruder. The effects of residence time and concentration of initiator and monomers on degree of grafting and gel content of grafting LDPE were studied systematically. Paraffin, styrene, p‐benzoquinone, triphenyl phosphite, tetrachloromethane, and oleic acid were added to try to decrease the extent of crosslinking of LDPE. 4‐hydroxyl‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy (4‐hydroxyl‐TEMPO) and dipentamethylenethiuram tetrasulfide were also tried to inhibit crosslinking reaction of LDPE during its extruding grafting process. It was found that p‐benzoquinone, triphenyl phosphite and tetrachloromethane were good inhibitors for crosslinking of LDPE. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 535–543, 2001     

Barrier properties of a thermotropic liquid‐crystalline polymer

A developmental thermotropic liquid‐crystalline polymer (TLCP) made by Eastman (trade name LN001) was used for barrier property studies. This material is a highly aromatic TLCP with a T_m of 332°C. A permeability study was carried out to determine the chemical resistance of the TLCP. The permeability of methanol and toluene through a membrane of the TLCP was studied using a two‐part cell and a gas chromatograph to monitor the flux. The membranes of the TLCP and LDPE (as control) were made by compression molding. Both solvents had higher permeability through LDPE than TLCP and that of toluene was higher than that of methanol. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2457–2463, 2003     

Intumescent fire-retardant coatings for plastics based on poly(vinylphosphonic acid): Improving water resistance with comonomers

Coatings based on the in situ photopolymerization of vinyl phosphonic acid (VPA) with triallyl cyanurate as a crosslinking agent are shown to be effective not only for fire-protecting glass fiber-reinforced epoxy resin (GRE) composites but also poly(methyl methacrylate) (PMMA), a typical meltable and flammable thermoplastic. Dry adhesion of polyVPA coatings to PMMA surfaces is excellent but, as with coatings on GRE, adhesion following water-soak tests is poor. Copolymerizing VPA with more hydrophobic monomers improves wet adhesion, albeit with some impairment of fire performance, with copolymers of VPA and acrylonitrile giving the best results. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47601.     

Nonisothermal crystallization kinetics of linear bimodal–polyethylene (LBPE) and LBPE/low‐density polyethylene blends

Nonisothermal crystallization kinetics of linear bimodal–polyethylene (LBPE) and the blends of LBPE/low‐density polyethylene (LDPE) were studied using DSC at various scanning rates. The Avrami analysis modified by Jeziorny and a method developed by Mo were employed to describe the nonisothermal crystallization process of LBPE and LBPE/LDPE blends. The theory of Ozawa was also used to analyze the LBPE DSC data. Kinetic parameters such as, for example, the Avrami exponent (n), the kinetic crystallization rate constant (Z_c), the crystallization peak temperature (T_p), and the half‐time of crystallization (t_1/2) were determined at various scanning rates. The appearance of double melting peaks and double crystallization peaks in the heating and cooling DSC curves of LBPE/LDPE blends indicated that LBPE and LDPE could crystallize, respectively. As a result of these studies, the Z_c of LBPE increases with the increase of cooling rates and the T_p of LBPE for LBPE/LDPE blends first increases with increasing LBPE content in the blends and reaches its maximum, then decreases as the LBPE content further increases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2431–2437, 2003     

Photopolymerizable bisallylcarbonate and bisacrylic monomers useful in the formulation of dental composite resins and in the crosslinking of methyl methacrylate

Two new bisallylic monomers [allyl p‐allyl carbonate benzoate (ApACBz) and 1,4‐phenylenbis(methylene)diallyl carbonate (1,4‐FMDAC)] and one bisacrylic monomer [1,4‐bis(acryloyloxymethyl)benzene (1,4‐BAMB)] were synthesized and used as crosslinking agents of methyl methacrylate (MMA) at different mass ratios (10, 20, 40, and 50%). All of the obtained copolymers showed improved thermal stability in comparison with that of the MMA homopolymer. Also, ApACBz and 1,4‐FMDAC were used as bisphenol A glycidyl methacrylate (Bis‐GMA) eluents to prepare dental resin composites. When compared to the control, the Bis‐GMA–new eluent composites had a higher double‐bond conversion, a higher solubility (p < 0.05) and a lower flexural strength (p < 0.05), whereas the elastic modulus and water sorption values were not statistically different (p > 0.05). The 1,4‐FMDAC and ApACBz monomers are promising eluents of Bis‐GMA for the preparation of dental composites with high degrees of conversion. In addition, the ApACBz, 1,4‐FMDAC, and 1,4‐BAMB monomers are potentially useful crosslinking agents when polymer networks of poly(methyl methacrylate) with a high thermal stability are desired. The application‐oriented tests of the monomers in dental composite formulations showed a sufficient storage stability, high photocuring activity, excellent crosslinking of MMA, and good thermal and mechanical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42920.     

Effect of crosslinkers on the preparation and properties of ETFE‐based radiation‐grafted polymer electrolyte membranes

This study concerns a comparative study of three crosslinkers, divinylbenzene (DVB), 1,2‐bis(p,p‐vinylphenyl)ethane (BVPE), and triallyl cyanurate (TAC) crosslinked poly(ethylene‐co‐tetrafluoroethylene) (ETFE)‐based radiation‐grafted membranes, which were prepared by radiation grafting of p‐methylstyrene onto ETFE films and subsequent sulfonation. The effect of the different types and contents of the crosslinkers on the grafting and sulfonation, and the properties such as water uptake, proton conductivity, and thermal/chemical stability of the resulting polymer electrolyte membranes were investigated in detail. Introducing crosslink structure into the radiation‐grafted membranes leads to a decrease in proton conductivity due to the decrease in water uptake. The thermal stability of the crosslinked radiation‐grafted membranes is also somewhat lower than that of the noncrosslinked one. However, the crosslinked radiation‐grafted membranes show significantly higher chemical stability characterized in the 3% H₂O₂ at 50°C. Among the three crosslinkers, the DVB shows a most pronounced efficiency on the crosslinking of the radiation‐grafted membranes, while the TAC has no significant influence; the BVPE is a mild and effective crosslinker, showing the moderate influence between the DVB and TAC crosslinkers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4565–4574, 2006     

Photoinduced crosslinking of polyolefine blends. I. Crosslinking of LDPE,PP, and LDPE/PP blends

Photocrosslinking of low-density polyethylene, (LDPE), polypropylene (PP) and their blends was investigated using xanthone and triallyl cyanurate as a photoinitiator and a coagent, respectively. The influence of the change of UV-irradiation conditions on the yield of photoinitiated processes was found to be very similar at any composition, while the crosslinking efficiency decreases with increase of PP content in the blend. The mechanism of the TAC action in photocrosslinking process was proposed and the effect of TAC reactions is discussed with regards to the effectivity of crosslinking of LDPE, PP, or the blends. © 1995 John Wiley & Sons, Inc.     

Copolymerization of alkyl acrylates with triallyl cyanurate: Kelen-Tüdös method applied for determining copolymerization reactivity ratios

The copolymerization of methyl acrylate (MA), ethyl acrylate (EA), straight-chain butyl acrylate (n-BA) and styrene (S) with triallyl cyanurate (TAC) has been studied in bulk at 343±1 K using benzoyl peroxide as initiator. The reactivity ratios of the monomers are determined by the Fineman-Ross (F-R) method and compared to those determined by the Kelen-Tüdös (K-T) method.     

Boiling water aging of polycarbonate and polycarbonate/acrylonitrile–butadiene–styrene resin and polycarbonate/low‐density polyester blends

The effects of boiling water on the mechanical and thermal properties and morphologies of polycarbonate (PC), PC/acrylonitrile–butadiene–styrene resin (PC/ABS), and PC/low‐density polyester (PC/LDPE) blends (compositions of PC/ABS and PC/LDPE blends were 80/20) were studied. PC and the PC/ABS blend had a transition from ductile to brittle materials after boiling water aging. The PC/LDPE blend was more resistant to boiling water aging than PC and the PC/ABS blend. The thermal properties of glass‐transition temperature (T_g) and melting temperature (T_m) in PC and the blends were measured by DSC. The T_g of PC and PC in the PC/ABS and PC/LDPE blends decreased after aging. The T_g of the ABS component in the PC/ABS blend did not change after aging. The supersaturated water in PC clustered around impurities or air bubbles leading to the formation of microcracks, which was the primary reason for the ductile–brittle transition in PC, and the microcracks could not recover after PC was treated at 160°C for 6 h. The PC/ABS blend showed slightly higher resistance to boiling water than did PC. The highest resistance to boiling water of the PC/LDPE blend may be attributed to its special structural morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 589–595, 2003     

Fire retardance in polyamide‐6. The effects of red phosphorus and radiation‐induced cross‐links

Red phosphorus contained in non‐irradiated polyamide‐6 at concentrations up to 12.5 does not significantly improve the fire resistance of the polymer. It weakens the thermal stability of the polymer as reflected by a decrease in the onset temperature for mass loss from 407°C to 363°C, but causes char formation as indicated by m_res=13 wt%, the non‐volatile residue at 600°C. Irradiation of polyamide‐6, loaded with red phosphorus, with ⁶⁰Co‐γ‐rays generates intermolecular cross‐links resulting in an improved fire resistance. However, the absorbed dose necessary to achieve improvement is too high (>1 MGy) from a practical point of view. This inconvenience is overcome by applying triallyl cyanurate (TAC) as a cross‐linking promoter. Typically, polyamide‐6 containing 5 wt% TAC and 12.5 wt% red phosphorus exposed to a γ‐ray dose of 22 kGy yields a V‐0 rating (in the mode A UL 94 test) concurrently with a small increase in the onset temperature for mass loss and a drastic increase in the residue non‐volatile at 600°C. Copyright © 2002 John Wiley & Sons, Ltd.     

Graft copolymerization of oleic acid onto low‐density polyethylene in the molten state

A graft copolymer of oleic acid (OA) onto low‐density polyethylene (LDPE) was prepared using dicumyl peroxide (DCP) as an initiator in the molten state. The grafting was carried out in a Haake rheometer. The effects of the reaction time and the amount of DCP and the monomer on the percentage of grafting were studied. The rheological behavior and the melt‐flow rate of the graft copolymer (LDPE‐g‐OA) were also investigated. FTIR spectroscopy and a mass spectrum were used to characterize the structure of LDPE‐g‐OA. The experimental results showed that when the OA amount was 10 wt % and the DCP amount was 0.4 wt % based on the LDPE the percentage of grafting of LDPE‐g‐OA, prepared by maintaining the temperature at 170°C and the roller speed at 80 rpm, was about 6 wt %. It was found that both LDPE and LDPE‐g‐OA were pseudoplastic fluids. OA was grafted onto LDPE in the form of a monomer and a dimer. The grafted LDPE is expected to act as a compatibilizer between starch and polyethylene. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3299–3304, 2003     

Synthesis and characterization of poly (amide-imide-imide)s based on diacids with bulky m-chloro phenyl moiety and rigid pyridine moiety

A series of novel aromatic diamines containing kinked m-chloro phenyl moiety was synthesized by the reaction of m-chloro benzaldehyde with 2,6-dimethyl aniline. The tetraimide diacid was synthesized by using the prepared diamine with benzophenone tetracarboxylic acid dianhydride (BPTDA) and p-amino benzoic acid. The polymers were prepared by treating the tetraimide diacid with different aromatic diamines. The structures of the monomers and polymers were identified by ¹H-NMR, FTIR,¹³C-NMR and elemental analysis. The polymers showed excellent thermal stability, solubility and mechanical properties. Their structure–property relationship was studied by comparing these m-chloro polymers with polymers containing rigid Pyridine moiety.     

Synthesis and characterization of novel organotin monomers and copolymers and their antibacterial activity

Two novel organotin monomers, (N‐tri‐n‐butyltin) maleimide and m‐acryloylamino‐(tri‐n‐butyltin benzoate), were synthesized. Copolymerization of these two monomers with styrene was carried out in the bulk at 65°C using asobisisobutyronitrile as the free radical initiator. The monomers and copolymers were characterized by elemental analysis; the molecular weights of the copolymers were determined by GPC, solubility, IR, and ¹H‐NMR spectral studies. The antibacterial activities of the synthesized organotin monomers and copolymers toward various types of bacteria were also reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 740–745, 2000     

Main‐chain liquid‐crystalline polymers containing azobenzene mesogen having long lateral aliphatic side chain: effect of copolymerization on thermal and phase behaviors

Homo‐ and copolyesters of derivatives of hydroxyazobenzenecarboxylic acid with various percentage compositions of m‐hydroxy benzoic acid (m‐HBA)/p‐hydroxy benzoic acid (p‐HBA) were synthesized and characterized. The properties of the copolyesters were compared with their corresponding homopolyesters. The solubility of the copolyesters with m‐HBA increased because of the decrease in the rigidity of the polymer chain attributed to the introduction of nonlinear molecules, whereas the solubilities of the copolyesters with p‐HBA changed only slightly compared to their corresponding homopolyesters. Thermal and phase behaviors of the polymers were characterized by TGA, DSC, and polarizing light microscopy (PLM) methods. Above 30% composition of m‐HBA, the thermal stability of the copolyesters with m‐HBA decreased compared to that of the homopolyester P1, whereas the copolyesters of p‐HBA possessed greater thermal stability than that of their homopolyesters at all compositions. The introduction of the long, flexible alkyl side chain laterally to the backbone of the azobenzene moiety drastically reduced the transition temperature of the homopolyester, but without destroying the mesophase. The effect of copolymerization on liquid‐crystalline behavior and transition temperature of the copolymers was discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1976‐1982, 2004     

Investigation of molecular structure of LDPE modified by itaconic acid grafting

Using thermomechanical spectroscopy, the molecular‐weight distribution and relaxation transitions have been investigated in commercial LDPE and grafted by itaconic acid (LDPE‐g‐IA). This grafting in the molten LDPE was done by reactive extrusion with varied content of reactants in the blend under alternating of a shearing rate applied onto the melt. The dependence of structural relaxation changes in LDPE is shown upon the depth of the mechanochemical transformations and the competing reactions at IA grafting, and also on the chemical crosslinking of the macromolecules. The reason for MWD bimodality for LDPE‐g‐IA obtained in dynamic mixing is the raised homogenization degree of the reactive blend and the higher grafted product yield compared with static mixers. The mixer type substantially affects the structure of the LDPE‐g‐IA amorphous phase. The data obtained reflect chemical transformations of LDPE molecules in IA's presence without an initiator of radical reactions (DCP). Most probable is the IA initiation of molecular crosslinking reactions. There could also occur IA thermodegradation and oligomerization. LDPE and IA or products of acid chemical transformations do not agree thermodynamically (the calculated solubility parameters are 16.1 (MJ/m³)^0.5 for polyethylene and 26.4 (MJ/m³)^0.5 for IA). From the above procedure it can be supposed that nongrafted IA (or its oligomers) exerts an antiplastifying effect on LDPE and LDPE‐g‐IA. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1771–1779, 1999     

Cashew nut shell liquid–based tailor‐made novolac resins: Polymer morphology quantitation by 1‐D and 2‐D NMR techniques and performance evaluation

The application of cashew nut shell liquid (CNSL) and CNSL‐based polymers in the burgeoning microelectronics industry is rare. “High ortho” alternating and semialternating tailor‐made novolac copolymers based on CNSL and m‐cresol and/or p‐cresol and have been made and successfully used as photoresists for microlithography. The microstructure of one of the representative m‐cresol copolymer is exhaustively elucidated based on 1‐D and 2‐D NMR techniques. Incorporation of different monomers in the resin backbone has been quantitatively estimated based on an improved NMR methodology. The lithographic performance of photoresists using novolac resins based on cardanol (fractionated CNSL) and diazonaphthoquinone ester was also evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1959–1965, 2003     

Effects of rosin‐type nucleating agent and low density polyethylene on the crystallization process of polypropylene

In this article, the influence of rosin‐type nucleating agent (Nu–Na) and low density polyethylene (LDPE) on the crystallization process of polypropylene (PP) from the melt state was studied by differential scanning calorimeter and polarization microscope. It was found that LDPE obstructed the crystallization of PP, decreased the crystallization rate of PP. The rosin‐type nucleating agent Nu–Na substantially improved the rate of crystallization, and decreased the size of spherulites also. The cooperative effect of LDPE and Nu–Na made the crystallization rate of PP increase greatly, the spherulites of PP became much smaller and dispersed more uniformly, and the transparency of PP was further improved evidently. The crystallization temperature (T_c) and melting temperature (T_m) of PP and LDPE in PP/LDPE/Nu–Na (97:3:0.5) were not affected by the number of mixed passes—the nuclei migration from PP to PE had not happened in the mixed passes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2804–2809, 2003