Synthesis and Characterization of Poly(<Emphasis Type="Italic">N</Emphasis>-Isopropyl Acryl Amide)-g-Poly(Linoleic Acid)/Poly(Linolenic Acid) Graft Copolymers

To diversify edible oil thermoresponsive polymer composites, polymeric linoleic acid peroxide (PLina) and polymeric linolenic acid peroxide (PLinl) were obtained by the autoxidation of linoleic acid (Lina) and linolenic acid (Linl), respectively. The autoxidation of Lina and Linl under air at room temperature rendered waxy soluble polymeric peroxide, having a soluble fraction in chloroform of more than 91 wt% and containing up to 1.0 wt% of peroxide. The soluble polymeric oil macro-peroxide was used to initiate the free radical polymerization of N-isopropylacrylamide, NIPAM, resulting in PLina-g-PNIPAM and PLinl-g-PNIPAM graft copolymers, respectively. The PNIPAM content of the graft copolymers was calculated using the elemental nitrogen analysis of graft copolymers. Thermal analysis, FTIR, ¹H NMR, and SEM techniques were used in the characterization of the products. The hydrophobic effect of the fatty acid macro peroxides on the thermal response rate of the graft copolymers was investigated by means of swelling-deswelling behaviors in response to temperature change. They have a thermoresponsive character and exhibit a volume phase transition at approximately 27–30 °C, which is 1–4 °C lower than that of pure PNIPAM. A plastizer effect of PLina and PLinl in graft copolymers was observed, indicating a lower glass transition temperature than that of pure PNIPAM.     

Polymeric Linoleic Acid–Polyolefin Conjugates: Cell Adhesion and Biocompatibility

To diversify edible-oil polymer composite, polymeric linoleic acid (PLina) peroxide was obtained by the auto-oxidation of linoleic acid in a simple way for use as a macroinitiator in free radical polymerization of vinyl monomers. Peroxidation, epoxidation, and/or perepoxidation reactions of linoleic acid under air at room temperature resulted in PLina, having soluble fraction more than 91 weight percent (wt%), with molecular weight ranging from 1,644 to 2,763 Da, and containing up to 1.0 wt% of peroxide. PLina initiated the free radical polymerization of ether styrene (S), methyl methacrylate (MMA), or n-butyl methacrylate (nBMA) to give PLina-g-polystyrene (PS), PLina-g-poly-MMA (PMMA), and PLina-g-poly- nBMA (PnBMA) graft copolymers. The polymers obtained were characterized by proton nuclear magnetic resonance (¹H NMR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC) techniques. Microstructure of the graft copolymers was observed by using scanning electron microscope (SEM). Graft copolymers obtained contained polymeric linoleic acid in a range between 8.5 and 19.3 mol percent (mol%). PLina-g-PS, PLina-g-PMMA and PLina-g-PnBMA graft copolymer samples were also used in cell culture studies. Fibroblast and macrophage cells were strongly adhered and spread on the copolymer film surfaces. These newly synthesized copolymers were tested for their effects on human blood protein adsorption compared with PMMA graft copolymers containing polymeric soybean oil and polymeric linseed oil; interestingly we observed a dramatic decrease in the protein adsorption on the linoleic acid graft copolymer, which is important in tissue engineering.     

Efficient synthesis of two or multi component block copolymers through living radical polymerization with polymeric photoiniferters

Summary To synthesize efficiently block copolymers, the radical polymerization of vinyl monomers with the polymers obtained by tetraethyl thiuram disulfide(TD) as polymeric photoiniferters has been investigated. These photopolymerizations were found to proceed via a living radical mechanism, i.e. both the whole polymer yields and the average molecular weight of the block copolymers increased with increasing of the polymerization time. By applying these living radical polymerizations, various block copolymers consisting of two, three and four component blocks were obtained in good yields, suggesting that these techniques are effective and useful for synthesizing multi component block copolymers through radical polymerizations of polar vinyl monomers.     

Synthesis and characterization of ozonized polyethylene

Polyolefins (LDPE and HDPE) can be ozonized with ozone/air gas flow to create peroxide and hydroperoxide groups on polymers. These reactive groups can be used to initiate radical polymerization of vinylic monomers and produce graft copolymers. In this study, the optimization of the experimental conditions and the explanation of the phenomena occurring during the ozonization of polyolefins in a fluidized bed have been studied. The most reproducible methods for placing peroxide and hydroperoxide groups onto polyolefins are the iodometric method and indirect titration by thiol. This work shows that it is necessary to control the temperature of the fluidized bed to avoid the acceleration of the reaction and the degradation of the polymers. Then, we studied the effect of different parameters such as the crystallinity and the granulometry of polymers, the time of ozonization and the effect of the load of the reactor on the quality of ozonization. Infrared spectroscopy and steric exclusion chromatography were used to characterize the ozonized polymers. We show that double bonds of PE, particularly vinyl groups, are very reactive to ozone and that ozonized HDPE leads essentially to the formation of hydroperoxide groups, whereas ozonized LDPE leads to the formation of peroxide groups.     

One-Pot Synthesis of Poly(linoleic acid)-g-Poly(styrene)-g-Poly(ε-caprolactone) Graft Copolymers

One-pot synthesis of graft copolymers by ring-opening polymerization and free radical polymerization using polymeric linoleic acid peroxide (PLina) is reported. Graft copolymers having structures of poly(linoleic acid)-g-polystyrene-g-poly(ε-caprolactone) were synthesized from PLina, possessing peroxide groups on the main chain by the combination of free radical polymerization of styrene and ring-opening polymerization of ε-caprolactone in one-step. Principal parameters, such as monomer concentration, initiator concentration, and polymerization time, which effect the one-pot polymerization reactions were evaluated. The obtained graft copolymers were characterized by ¹H-NMR and DOSY-NMR spectroscopy, gel permeation chromatography, thermal gravimetric analysis and differential scanning calorimetry techniques.     

Edible oil quality as measured by thermal release of pentane

As part of their thermal decomposition products, fatty hydroperoxides produce normal hydrocarbons. The extent of hydrocarbon formation can be measured and associated with the quality and potential stability of an oil. Edible oils containing linoleic acid develop 13-hydroperoxy-9,11-octadecadienoic acid as one product of autoxidation. On thermal decomposition this hydroperoxide yields pentane; the amount released has been correlated with the flavor scores of fresh and aged soybean and cottonseed oils and with the peroxide values of these oils. The quantity of pentane released has an inverse linear relationship to flavor score and a direct linear relationship to peroxide values. Edible oils exposed to light exhibit a different relationship between flavor score and thermally derived pentane than do the same oils when autoxidized in the dark. Presented at AOCS Meeting, New Orleans, May 1967.     

Preparation of grafted copolymers via oxidized polypropylene

A new and novel class of oxidized polypropylene containing bound peroxide functionalities can be used as polymerization initiators to produce polypropylene‐grafted copolymers. Upon heat treatment, the peroxide functionalities in the oxidized polypropylene act as a source of free radicals, reacting with the unsaturated double bonds of the monomer and initiating polymerization. The grafting reaction is carried out in the solid state in a reactor. The advantage of grafting via this new class of oxidized polypropylene is the elimination of expensive and environmentally unfriendly organic peroxides. A number of monomers have been grafted using oxidized polypropylene, including vinyl acetate, vinyl pyrrolidinone, methacrylic anhydride, and maleic anhydride. Oxidized polypropylene‐grafted copolymers are effective compatibilizers for PP/ETP blends and good coupling agents in glass‐ reinforced formulations. Preparation, characterization, and mechanical properties of terpolymers prepared from sequential grafting of oxidized polypropylene are also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

复杂聚合物链结构的可控制备与新材料

自由基聚合与配位聚合的产物通常为宽分子量分布的均聚物或无规共聚物。近二十年来,活性/可控自由基聚合、活性/可控配位聚合、链穿梭聚合的研究取得突破。这些方法使得几乎所有的乙烯基单体,特别是廉价易得的单体,都可用作原料来制备原来无法制备得到的两嵌段、多嵌段共聚物、梯度共聚物等更为复杂聚合链结构。合理设计这些复杂的链结构,有望得到高性能、高附加值合成材料。介绍了这些新型聚合原理的机理、新进展,讨论了它们潜在的应用前景。     

Long-lived polymer radicals

Summary When N-acryloyl-L-valine(ALV) was photo-polymerized in ethyl acetate, the resulting polymerization mixture was found to contain the living propagating radical of ALV. Synthesis of block copolymers was attempted by using the reaction of living poly(ALV) radical with some vinyl monomers. The resulting block copolymers were characterized by IR spectroscopy, dynamic thermogravimetry and pyrolysis gas chromatography.     

Graft polymers with macromonomers. I. Synthesis from methacrylate-terminated polystyrene

Pure graft polymers having uniform molecular weight polystyrene side chains were prepared by free radical copolymerization of methacrylate-terminated polystyrene macromonomers (MA-CROMER) with ethyl acrylate, butyl acrylate, or other suitable monomers. The MACROMER monomer was synthesized by living anionic polymerization under conditions that led to very narrow molecular weight distributions. Very effective end capping produced a material that was highly monofunctional. The graft copolymers were prepared by several techniques such as free radical solution polymerization, by aqueous suspension polymerization which produced beads, or by emulsion reactions which yielded stable latices. Polymerizations were reproducible. High conversion of the MACROMER monomer into pure graft polymers was achieved, and the product was contaminated with only a little homopolymer. The milled and molded phase-separated graft polymers had optical clarity and physical properties characteristic of polystyrene-reinforced triblock polymers. Compositions of 20-30% polystyrene were thermoplastic elastomers with good recovery. When polystyrene contents were increased, the graft products were strong, flexible thermoplastics with well defined yield strengths and increased permanent set. Copolymers of polystyrene macromers with acrylonitrile or vinyl chloride produced transparent polystyrene homopolymer-free graft polymer products having improved processing over polyacrylonitrile or poly(vinyl chloride) homopolymers.     

Radical polymerization of itaconic anhydride and reactions of the resulting polymers with amines and alcohols

Itaconic anhydride was polymerized in the presence of a radical initiator under various conditions. The bulk polymerization at 75°C yielded polymer with molecular weight of more than 20000. The reactions of the resulting polymer with water and alcohols gave poly(itaconic acid) and its esters, respectively. The polymers prepared by such reactions were found to have similar thermal properties to those prepared by homopolymerizations of the respective itaconic acid derivatives. Poly(N-substituted itaconomic acid)s, which are difficult to obtain by direct polymerization of their monomers, were prepared by the reactions of poly(itacononic anhydride) with amines. Copolymerizations of itaconic anhydride with electron-donating monomers, styrene and isobutyl vinyl ether, gave alternating copolymers which were then converted by esterification to the respective copolymers of dialkyl itaconates with such electron-donating monomers.     

活性自由基聚合反应与多种结构聚合物的制备

介绍了原民移自由基聚合反应这一新型的活性自由基聚合方式,并综述了利用这种聚合方法制备的多种结构的聚合物,包括嵌段共取物,交替共聚物,接枝共聚物,星形聚合物,超支化聚合物,梳形聚合物等。     

Stereoselective alternating copolymerization of aliphatic acetylenes with sulphur dioxide

A number of purified terminal aliphatic acetylenic hydrocarbons has been copolymerized with liquid sulphur dioxide in the presence of t-butyl hydroperoxide at low temperature. Benzoyl peroxide, hydrogen peroxide and m-chloroperbenzoic acid were ineffective. Neither sulphur dioxide nor t-butyl hydroperoxide alone was capable of polymerizing pure alkynes. Aged (impure) alkynes were copolymerized with sulphur dioxide in the absence of t-butyl hydroperoxide. All resulting alkyne-SO₂ copolymers were alternating with 100% trans configuration regardless of the nature of the alkyne, the solvent, or temperature. Several studies were performed to characterize the polysulphones, such as infra-red spectroscopy, ¹H and ¹³C nuclear magnetic resonance spectroscopy, melting point, viscosity, elemental analysis, solubility, film formation and flammability. A mechanism is proposed in which sulphur dioxide homolytically decomposes the organic hydroperoxide into free radicals which initiate the polymerization. The alkyne-SO₂ charge transfer complex is formed in solution, and the initiation and propagation steps probably involve this complex in equilbrium with its monomers.     

Studies on the grafting of acryloylated potato starch with styrene

An investigation of graft polymerization to determine the potential of a starch‐bonded acryloyl group as a suitable coupling agent with vinyl monomers was carried out. In this case, potassium persulfate was used as a free‐radical initiator using water as the reaction solvent for further graft polymerization. This work revealed the ability of water as a reaction medium; perhydroxyl and hydroxyl radicals were easily formed from persulfate to produce free radicals to activate the styrene monomer towards grafting with acryloylated potato starch. The graft copolymers were characterized by FT‐IR spectroscopy and further confirmed using saponification. The analysis results showed the grafted potato starch with the styryl chain afforded protection to the ester bond, which resisted the alkaline hydrolysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 452–459, 2005     

Chemoenzymatic epoxidation of unsaturated fatty acid esters and plant oils

In the presence of an immobilized lipase fromCandida antacrtica (Novozym 435^R) fatty acids are converted to peroxy acids by the reaction with hydrogen peroxide. In a similar reaction, fatty acid esters are perhydrolyzed to peroxy acids. Unsaturated fatty acid esters subsequently epoxidize themselves, and in this way epoxidized plant oils can be prepared with good yields (rapeseed oil 91%, sunflower oil 88%, linseed oil 80%). The hydrolysis of the plant oil to mono- and diglycerides can be suppressed by the addition of a small amount of free fatty acids. Rapeseed oil methyl ester can also be epoxidized; the conversion of C=C-bonds is 95%, and the composition of the epoxy fatty acid methyl esters corresponds to the composition of the unsaturated methyl esters in the substrate. Based partly on a lecture at the 86th AOCS Annual Meeting & Expo, San Antonio, Texas, May 7–11, 1995.     

Studies on the graft polymerizations of styrene and methyl methacrylate to hydroxyl terminated polybutadiene

Hydroxyl terminated Polybutadiene (HTPB) was grafted with styrene (St) or methyl methacrylate (MMA) by free radical solution polymerization. The graft copolymerizations were conducted in benzene at 70 °C. The initiators used were benzoyl peroxide (BPO) and azobis-isobutyronitrile (AIBN). The microstructures of theobtained graft copolymers were characterized by¹³C NMR measurement and the DEPT technique, as well as by IR spectrometer. The mechanism of grafting reactions was determined from the microstructures of derived graft copolymers. It showed that graft copolymer resulted when BPO was used as initiator of the vinyl monomer polymerization, but not with AIBN. It appeared that the reaction leading to graft formation was direct attack of oligomeric styrene radicals or double bonds of the HTPB. Whereas the graft copolymerization of MMA to HTPB was the same as that suggested in the literature i.e., by a hydrogen abstract reaction.     

Beitrag zur kenntnis der polymerisationsanregung mit redoxsystemen,die metallverbindungen enthalten

Apart from the redox system peroxide/vanadium accelerator, only the combination hydroperoxide/cobalt (II) salt has obtained industrial importance for the free – radical initiated polymerization of unsaturated polyester resins at room temperature. Other metal compounds either do not react with peroxides to form radicals or only do so at a very low rate. It has been found that the presence of promotors or additional accelerators not only increases the action of cobalt compounds, but also activates compounds of manganese, copper and iron to such a degree that they can be used for initiating the polymerization of unsaturated polyester resins at room temperature. The following compounds were used as promotors in the investigations: N,N-dimethylaniline, t-dodecyl mercaptan, n-dodecyl mercaptan, sodium benzenesufiate, a-hydroxymethyl phenylsulfone, N-methyl-bis-(phenylsulfonemethyl)amine, ethyl acetoacetate, acetylacetone, and acetoacetdiethylamide. When these promotors are used merely in conjunction with peroxides, there is no formation of radicals or the rate of radical formation is only low. In contrast to this, the combination peroxide/metal compound/promotor has a remarkably high effectiveness as a polymerization initiator. The use of redox systems of this type is not confined to initiate polymerization of unsaturated polyester resins. They are also suitable for polymerizing other systems which can be subjected to free-radical initiated polymerization, e. g. acrylate syrups, styrene syrups and monomers. For each monomer system the optimum combination must be ascertained. In some cases it was possible to throw some light on the mode of action of the promotor.     

Capillary gas chromatographic analyses of headspace volatiles from vegetable oils

Eight different vegetable oils obtained commercially were analyzed for volatiles by capillary gas chromatography (GC). Volatiles generated in a GC static headspace sampler at 180 C were injected automatically onto a chemically bonded capillary column. Only a small number of GC peaks of low intensity were observed in the fresh samples, which varied in peroxide values from 0.2 to 3. Several major peaks were evident in the oils aged eight and 16 days at 60 C with peroxide values ranging from 16 to 65. Thirty-four GC peaks were identified on the basis of relative retention time of reference compounds and on the basis of gas chromatography-mass spectrometry (GC-MS). Volatile compounds identified were those expected from the autoxidation of principal unsaturated fatty acid components of each vegetable oil tested. The relative concentrations of volatile components increased with the level of oxidation as determined by peroxide value. Presented at the AOCS Meeting in Chicago, May 1983.     

Acroleindiethylacetal: Reaction with free radicals and copolymerization

The reaction between acroleindiethylacetal (3.3-diethoxypropene) and free radicals and the behaviour of this acetal in the free radical copolymerization with unsaturated monomers has been investigated. The decomposition of benzoyl peroxide and tert.-butyl peroxide in acroleindiethylacetal has been studied in the liquid phase. On the basis of the obtained products a mechanism is proposed which involves the abstraction of a hydrogen atom by a primary radical from a carbon atom which is adjacent to oxygen. We also tried to copolymerize the acetal with several conventional comonomers but copolymers were only obtained when acrylonitrile and maleic anhydride were used. The remarkably uniform composition of the copolymers from the acetal and maleic anhydride is explained through a donor-acceptor complex between the two monomers.     

Chemical Properties and Fatty Acid Composition of Thunbergia fragrans Roxb. Seed Oil

The physicochemical and fatty acid compositions of seed oil extracted from Thunbergia fragrans were determined. The oil content, free fatty acids, peroxide value, saponification value and iodine value were 21.70 %, 2.25 % (as oleic acid), 9.6 (mequiv. O₂/kg), 191.71 (mg KOH/g) and 127.84 (g/100 g oil) respectively. The fatty acid profiles of the methyl esters showed the presence of 90.16 % unsaturated fatty acids and 9.84 % saturated fatty acids. Palmitoleic acid, which is usually found in marine foods and is unique in seed oils of botanical origin, was the major component (79.24 %). The oil can also be used in industries for the preparation of liquid soaps, shampoos and alkyd resin.