Homo-and copolymers of vinyl esters,acrylates, and methacrylates of some derivatives of fatty acids

Vinyl esters of some undecylenic acid derivatives and acrylates and methacrylates of undecyl and undecylenyl alcohols, which may be considered as derivaties of castor oil, have been polymerized and copolymerized with vinyl chloride to provide a variety of new polymers. The acrylate and the methacrylate of undecylenyl alcohol have been epoxidized to yield two new polymerizable monomers of potential usefulness as crosslinking agents in finished copolymers.     

Thermoresponsive poly(oligo ethylene glycol acrylates)

Thermoresponsive polymers have been the subject of numerous publications and research topics in the last few decades mostly driven by their easily controllable temperature stimulus and high potential for in vitro and in vivo applications. P(NIPAAm) is the most studied amongst these polymers, but recently other types of polymers are increasingly being investigated for their thermoresponsive behavior. In particular, polymers bearing a short oligo ethylene glycol (OEG) side chain have been shown to combine the biocompatibility of polyethylene glycol (PEG) with a versatile and controllable LCST behavior. These polymers can be synthesized via controlled radical polymerization techniques from various monomers consisting of an OEG chain and a polymerizable group like a (meth)acrylate, styrene or acrylamide. OEG acrylates offer significant advantages over, e.g., OEG methacrylates as the lower hydrophilicity of the backbone facilitates thermoresponsive behavior with smaller, more defined side chains. Furthermore, PEG acrylates can be polymerized using all major controlled radical polymerization techniques, unlike OEG methacrylates. This review will focus on OEG acrylate based (co)polymers and will provide a comprehensive overview of their reported thermoresponsive properties. The combination and comparison of this data will not only highlight the potential of these monomers, but will also serve as a starting point for future studies.     

主链含三芳基氧化膦的阻燃工程塑料

叙述反应型磷系阻燃剂双（４－羧苯基）苯基氧化膦和双（４－羟苯基）苯基氧化膦故土的合成,以及以三芳基氧化膦为链段的含磷阻燃尼龙６６共聚物、共聚碳酸酯及聚芳酯的合成方法,讨论了按上述方法合成的阻燃工程塑料的阻燃性能     

苯乙烯系阻燃塑料合金的研究进展

综述了国内外近年来在苯乙烯系阻燃塑料合金方面的研究进展。主要介绍了高聚物型卤系阻燃剂、磷系阻燃剂、有机硅系阻燃剂的特性及其在提高苯乙烯系塑料合金阻燃性能方面的应用。与目前常用的低分子卤系阻燃剂相比，这些阻燃剂对环境污染小，对塑料基材的机械性能和加工性能损害程度少。此外，还简要介绍了纳米复合技术在提高苯乙烯系塑料阻燃性能中的应用。     

Localized radiation grafting of flame retardants to poly(ethylene terephthalate). I. Bromine-containing monomers

Vinyl bromide was used as a model for bromine-containing flame retardants in developing methodology for localizing flame retardants either on the surface of the filament, uniformly throughout it, or predominantly at the core. SEM–x-ray microprobe techniques were used in the verification of the location of the flame retardant in the filament. The flame retardance efficiency of PVBr was then correlated with its location in the filament. Grafting other bromine-containing flame retardants showed a wide range of efficiencies which depended not only upon the location of the grafting within the filament but also upon the structure of the compound. For the various bromine homopolymer grafts, the apparent thermal stability of the graft and its flame retardance efficiency may be simply related to the alpha aliphatic hydrogen-to-bromine ratio. The lower this ratio is, the higher the efficiency. VBr copolymers and terpolymers showed wider variation in flame retardance efficiencies. This is attributed to large variations in melt viscosity of the different grafted materials. The grafts showed only small changes in their melting points and minimal changes in tenacity and stiffness. However, grafting induced large increases in the elongation.     

Copolymerization of 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methyl acrylate and (10‐oxo‐10‐hydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl) methyl acrylate with styrene and their thermal degradation characteristics

Two phosphorus‐containing acrylates of 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methyl acrylate and (10‐oxo‐10‐hydro‐9‐oxa‐10λ⁵‐phosphaphenanthrene‐10‐yl) methyl acrylate were free‐radical‐copolymerized with styrene (St). The r₁ reactivity ratio values (related to the novel acrylates) were 0.342 and 0.225, respectively, and the r₂ reactivity ratio values (related to St) were 0.432 and 0.503, respectively. The thermal stability of the copolymers was tested by thermogravimetric analysis (TGA) in N₂ or air, and the ignitability was tested by measurements of UL‐94 vertical combustion tests and the limiting oxygen index. The results of TGA and combustion tests indicated that the effect of flame retardancy was determined by the nature of the phosphorus‐containing substituent. Compared with the 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide based group, the 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methol based group could enhance the ability of char formation with an antidripping effect. It is concluded that phosphorus‐containing acrylates are potential flame‐retarding monomers for styrenic polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Use of DTA with infrared analysis of evolved gas to investigate the effect of flame retardants on gas evolution from pyrolysed cellulose (cotton)

DTA combined with infrared analysis of the evolved gas (EGA) has been used to study the temperature behaviour, both in air and nitrogen, of commercial phosphorus- and nitrogen- and/or bromine-containing flame retardants applied to cotton. By reference to the DTA traces and also the maxima occurring in the CO, CO₂ and H₂O evolution rates, seven significant peak temperatures were assigned. Two new relatively low temperature peaks have been observed: the higher of these is DTA-sensitive and occurs in all unretarded and retarded samples and is ascribed to the formation of an ‘activated cellulose’ state previously proposed by Bradbury, Sakai and Shafizadeh;¹⁷ the lower peak is an exotherm (188-220°C) associated with H₂O and CO₂ evolution from flame-retarded samples only. These observations are interpreted in terms of the mechanism of the cellulose pyrolysis/combustion and the influence of the flame retardants.     

Light stabilization of flame retardant impact polystyrene

This paper presents the results of a study onn the effectiveness of ultraviolet absorbers and light stabilizers in preventing the discoloration of flame retardant impact polystyrene. The deleterious effect of certain flame retardants, i.e., aromatic or aliphatic halogenated compounds, on the light stability of this polymer is shown. Light stabilizer systems resulting in substantially improved color stability during light exposure are presented. The beneficial effect df co-additives, including antioxidants, acid acceptors, epoxies, phosphites, and thiosynergists, on light stability is also discussed.     

Oxidation behavior of isoprene polymers and butadiene polymers

The oxidation behavior of cis-1,4-polyisoprene, emulsion polyisoprene, emulsion isoprene/styrene copolymers, and emulsion butadiene/styrene copolymers by heat aging or ultraviolet irradiation has been investigated from the change of gel fraction and molecular weight distribution. It was determined that the oxidation behavior of both isoprene and butadiene polymers is strongly dependent on the composition of the polymers as well as on the microstructure of the polymers. In the case of oxidation by heat aging, the probability ratio of chain scission to crosslinking of both isoprene and butadiene copolymers increases gradually with increasing styrene fraction. In the case of oxidation by ultraviolet irradiation, isoprene copolymers show a remarkable increase in the probability ratio of chain scission to crosslinking, whereas butadiene copolymers show substantially no change with increase in styrene fraction. It was also demonstrated that both isoprene and butadiene polymers show a greater tendency for crosslinking with oxidation by ultraviolet irradiation than with oxidation by heat aging.     

苯乙烯系阻燃塑料合金的研究进展

综述了国内外近年来在苯乙烯系阻燃塑料合金方面的研究进展。主要介绍了高聚物型卤系阻燃剂、磷系阻燃剂、有机硅系阻燃剂等阻燃剂的特性及其在提高苯乙烯系塑料合金阻燃性能方面的应用，这些阻燃剂对环境友好，不仅能显著提高塑料基材的阻燃性能，而且力学性能和加工性能也得到改善。此外，还简要介绍了纳米复合技术在提高苯乙烯系塑料阻燃性能中的应用。     

Metal Macrocyclic Complexes as Novel High Temperature Stabilizing Agents and Flame Retardants for Polymers

Abstract

Metal macrocyclic complexes are considered as noval high temperature stabilizing agents and flame retardants for polymers.     

Some properties of styrene‐based ionomers II

Some properties of styrene‐based ionomers obtained from copolymers styrene (S) and acrylic acid (AA) or methacrylic acid (MA) obtained in emulsion containing alkali metal salts have been investigated. A study has been conducted to examine the influence of the acid content and nature (acrylic or methacrylic) and nature of alkali metal salt on the glass transition temperature, density, melt index, and activation energy of flow of the styrene‐based ionomers. The present studies have indicated that the temperature of glass transition (T_g) of sodium ionomers increases as the sodium content rises, but the increase is lower than in the case of the ionomers based on copolymers obtained in bulk. The density of films rises with the content of alkali metal salt introduced to the polystyrene chain, and it is higher than in the case of the ionomers based on copolymers obtained in bulk containing almost the same content of alkali metal salts. Styrene ionomers containing alkali metal acrylates have higher densities than those containing alkali metal methacrylates. The melt index of the investigated ionomers depends on the amount and type of introduced acid and salt, as well as on the molecular weight of the initial copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 268–275, 2005     

The flammability of polyacrylonitrile and its copolymers III. Effect of flame retardants

This paper extends previously reported work ^1,2 and describes the influence that a range of selected flame retardants have on the burning behaviour and pyrolyses of homo-and copolymers of acrylonitrile. Various inorganic and organic phosphorus and nitrogen- or sulphur-containing, halogen-containing (in the absence and presence of halogen or antimony (III) oxide) and nitrogen-containing flame retardants and red phosphorus were studied using LOI, TGA, DSC and residual char measuring techniques. Flame retardancy relates directly to char-forming tendency for all retardants and their ability to reduce the dominance of flammable volatiles formed during the first stage of acrylic polymer pyrolysis. Ammonium phosphates are particularly effective flame retardants for the selected copolymers. Possible mechanisms of retardant activity are discussed, including the char-forming tendency of antimony–bromine combiniations.     

The polymerization and copolymerization of nitroalkyl acrylates and nitroalkyl methacrylates

Nitroalkyl acrylates and methacrylates involving some new compounds were prepared. The homopolymerization of these monomers in toluene and their copolymerization with styrene in acetone were carried out with azobisisobutyronitrile as initiator. The rate of polymerization of the nitroalkyl acrylates showed a correlation with the number of nitro groups situated on the ester side chain. The apparent activation energies of the polymerization were found to be 22.0–27.5 kcal./mole for the nitroalkyl acrylates and about 11.5–13.0 kcal./mole for the nitroalkyl methacrylates. From the reactivity ratios and Q-e values of the copolymerization the following information was obtained. The copolymerization behavior of nitroalkyl acrylates and methacrylates showed an alternating tendency, and these monomers belong to the conjugative monomer groups. On the reactivities of these monomers, the polarity of vinyl group was affected a little by nitro group of ester bond side, and the resonance affected little. These monomers were crosslinked with 2-methyl-2-nitro-1,3-propylene diacrylate. Some of the polymers showed marked improvement in the physical properties of elastomers.     

Transport of gases and vapors in methacrylic copolymers of varying side chain length

The gas transport properties of copolymers of dodecyl methacrylate with ethyl methacrylate and hydroxypropyl methacrylate have been studied. The diffusion, solubility and permeability of oxygen, nitrogen, carbon dioxide, methane, ethane and ethylene have been measured in the temperature range 0-50 °C, and activation energies and heats of solution have been obtained. A comparison with the data available in the literature on acrylates and other methacrylates of varying aliphatic side chain length has been performed. The diffusion coefficient of gases increases with the side chain length in a way similar to that found for homologous acrylates. A representation of log(D) as a function of the inverse of the fractional free volume shows that all acrylates and methacrylates of lineal alkyl side chain fall on the same straight line.     

Improving weathering resistance of flame‐retarded polymers

Most flame‐retarded polymer products need to be highly durable throughout their service lifetime in many demanding applications areas such as construction, transportation, electric equipment, and textiles, where low flammability in combination with high resistance toward oxidative deterioration triggered by the action of light, heat, and/or mechanical stress is a mandatory quality. To achieve this, it is essential to better understand the overall interplay (both physical and chemical processes) between different components such as different flame retardant structures in their respective polymers and in the presence of coadditives such as processing stabilizers, antioxidants, light stabilizers, metal deactivators, filler deactivators, ultraviolet absorbers, and so on, in the flame‐retarded polymer product. In this article, the key difficulties in improving weathering resistance of flame‐retarded polymers are reviewed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and polymerization of hydrophobic iodine-containing methacrylates

Starting from 2,4,6-triiodophenol, 2,3,5-triiodobenzoic acid and 3,5-bis(acetylamino)-2,4,6-triiodobenzoic acid, polymerizable methacrylates were synthesized and characterized by elemental analyses, IR, ¹H-NMR and ¹³C-NMR spectroscopy. The iodine-containing methacrylates show a different radical polymerization behaviour. 2,4,6-Triiodophenyl methacrylate gives only oligomeric products in the presence of azoisobutyronitrile (AIBN), whereas 2-methacryloyloxyethyl 2,3,5-triiodobenzoate yields polymers. On the basis of mixtures of isomeric 1,3-dimethacryloyloxy-2- and 1,2-dimethacryloyloxy-3-(2,3,5-triiodobenzoyloxy)propane with usual crosslinking monomers, radiopaque materials were prepared.     

Synthesis and characterization of polymers containing naphthyl-2H-benzotriazoles, 2. Polymer synthesis and characterization

2-(2-Hydroxy-7-(meth)acryloyloxynaphthyl)-2H-benzotriazoles were polymerized and copolymerized with styrene and methyl methacrylate in dichloromethane using azoisobutyronitrile as the initiator. The polymer composition was determined by UV spectroscopy and compared with elemental analytical data; the molecular weights were determined by GPC. In homopolymerization, low molecular weight products were obtained due to the bulky naphthyl-2H-benzotriazole units. In the case of copolymerization with methyl methacrylate it was found, that the composition of the polymers was very close to the initial ratio of the monomers, whereas in copolymers with styrene the amount of incorporated benzotriazole was higher.     

Some properties of copolymers of vinylidene chloride with acrylates and methacrylates,Part 1

Copolymers of vinylidene chloride (VDC) and acrylates or methacrylates were investigated by calorimetric (DSC) and infrared spectroscopic methods to determine glass transition temperature and crystallization behavior. The final crystallinity of some annealed copolymers of VDC and methyl acrylate (MA) or methyl methacrylate (MMA) was studied by means of WAXS measurements. It was found that: (i) the glass transition temperature of copolymers of VDC and acrylates goes through a maximum as a function of the composition. The maximum shifts toward higher concentrations of VDC in the copolymer with increasing length of the ester group. (ii) However, for copolymers of VDC and methacrylates one observes a monotonic rise in the glass transition temperature with increasing concentration of the methacrylate, that can be described by the equation of Gordon and Taylor. (iii) For a given comonomer, the crystallization rate increases with increasing VDC content and, moreover, for a given VDC content it is slowest with methyl acrylate and fastest with ethylhexyl acrylate. Therefore, for a given crystallization rate, the copolymers of VDC and methyl acrylate contain the highest weight fraction of VDC. However, on a molar basis the differences are rather small. Analogous behavior is observed for the copolymers of VDC and acrylates or methacrylates. (iv) The final crystallinity of the annealed copolymers decreases linearly with decreasing VDC content. From this linear decrease, the limiting VDC concentration for zero crystallinity was extrapolated to about 75 mol-% VDC. These values are slightly lower than those estimated from infrared spectroscopy. Consequently, the final crystallinity of the copolymers studied is influenced by the VDC content rather than by the comonomer type. (v) The final crystallinity of the VDC homopolymer is determined as 57 ± 2 wt.-% in agreement with literature data. The crystallinity of the copolymers of VDC with different acrylates or methacrylates can then be estimated as a function of the composition.     

Polymerization of alkyl acrylates and alkyl methacrylates with starch

A series of C₄-C₁₂ alkyl acrylates and methacrylates was polymerized with starch by irradiating starch–monomer mixtures with ⁶⁰Co. Homopolymers were extracted with cyclohexane. The amounts of insoluble versus soluble synthetic polymer in polymerization run with alkyl acrylates varied less with the chain length of the alkyl substuent than in the polymerizations run with alkyl acrylates varied less with the chain length of the alkyl substituent than in the polymerizations run with alkyl methacrylates; and the poly(alkyl acrylate) contents of cyclohexane-insoluble fractions were all in the 38–45% range. Synthetic polymer contents of the products from butyl, hexyl, and decyl methacrylates were also close to this range. Octyl and lauryl methacrylate, however, gave high conversions to cyclohexane-soluble poly(alkyl methacrylate) along with little or no unextractable synthetic polymer in the starch-containing fractions. Poly(lauryl methacrylate) could be rendered insoluble by incorporating a small amount of tetramethylene glycol dimethacrylate in the polymerization mixture. In a series of polymerizations run with hexyl acrylate and hexyl methacrylate, lower irradiation doses led to more cyclohexane-soluble polymer and less synthetic polymer in the starch-containing fractions. Enzymatic digestion of starch-soluble polymer and less synthetic polymer in the starch-containing fractions. Enzymatic digestion of starch-containing polymers gave synthetic polymer fractions that were largely insoluble in cyclohexane. Crosslinking is, therefore, probably taking place during these polymerizations; however, we could not eliminate the possibility that reduced solubility was caused by small amounts of residual carbohydrate in these polymer fractions. Ceric ammonium nitrate-initiated polymerizations of butyl acrylate, hexyl acrylate, and butyl methacrylate with starch gave cyclohexane-insoluble polymers that contained 33–39% synthetic polymer. The higher alkyl acrylates and methacrylates produced little or no polymer under these conditions. Starch-containing fractions were tested as absorbents for hydrocarbons. Products prepared from decyl acrylate and lauryl acryle acrylate absorbed about 9 g of isooctane per 1 g of polymer, whereas the lowrer alkyl monomers gave polymers with lower absorbency.