Syntheses of ultraviolet light absorbers for polyvinylchloride (PVC). Part I

The syntheses of the following ultravilot light absorbers from cashewnutshell liquid are described: 2-(2′-pentadecenyl-4′-hydroxy-phenyl)-benzotriazole, 2-(2′-pentadecyl-4′-hydroxy-phenyl)-benzotriazole, 2-(2′-pentadecyl-3′-carboxy-4′-hydroxy-phenyl)-benzotriazole, 2-(2′hydroxy-4′-pentadecyl-5′-chloro-phenyl)-benzotriazole, 2-(2′-hydroxy-4′-pentadecyl-benzophenone, 3-pentadecyl-phenyl-salicylate and nickel complex of di-(4-pentadecyl-6-hydroxy-phenyl)-sulfide.     

Modification of reinforced thermosetting plastic with ultraviolet radiation

Curing of filled systems previously treated with UV radiation is a first-order process with respect to the oligomers that takes place in the diffusion region. The slowing effect of viscose fibres in the initial stage of curing increases the impact strength of the reinforced material. The UV radiation increases the probability of linear chain growth during curing and results in material with a high average weight of crosslinked chains. UV treatment increases the impact strength and static bending breaking stress by 20–50% in comparison to materials obtained without irradiation and is an effective method of modification. The polymer reinforcement decreases the density and increases the strength characteristics of concrete articles in comparison to unreinforced concrete. __________ Translated from Khimicheskie Volokna, No. 1, pp. 45–48, January–February, 2008.     

紫外线持续消毒能力的研究

紫外线消毒技术不向水中投加任何化学药剂,因此不具有持续消毒能力。对消毒后中水在不同保存条件下和不同静置时间下细菌增殖情况进行了实验研究,结果表明:紫外线消毒后的中水在最初的6h内细菌增殖缓慢,光照比避光条件下细菌增殖快,因此,紫外线消毒后的中水宜在6h内使用,且配水管网应采用不透光材料。同时对紫外线消毒和氯消毒技术的联用进行实验,结果表明紫外线消毒后的中水在投加了0.2mg/L的有效氯后可以放置5d。     

Effect of ultraviolet radiation on photodegradation of collagen

Photodegradation of solvent-cast collagen type I films and photostabilization of collagen by vitamin E were studied. These films were exposed to polychromatic radiation from a medium-pressure mercury lamp or monochromatic radiation from the Okazaki Large Spectrograph (OLS). Changes in the molecular structure of collagen were followed by UV-visible and FTIR spectroscopic measurements. Electron spin resonance (ESR) spectroscopic measurements were also carried out to identify the reaction intermediates of photodegradation. Photoreaction from phenylalanine, which is one of the main constituents of collagen to tyrosine and the scission of peptide linkage of collagen, were confirmed. Vitamin E was found to be an efficient photostabilizer for photodegradation of collagen. Action spectra of photodegradation and photostabilization of a collagen molecule were reported. A possible mechanism for the photodegradation of the collagen and photostabilization scheme based on these experimental results are presented. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1259–1265, 1999     

紫外线对给水除藻作用的研究

以武汉东湖水为原水,采用不同的光强和照射时间组合,对原水进行紫外光预处理来加强除藻效果,后续工艺为栅条絮凝、气浮。试验结果表明:2.8mW/cm2照射1.5min可达到83.5%的除藻率,2.5mW/cm2照射6min除藻率为87.6%。光强和时间对藻的抑制存在交互作用,增大光强可提高除藻率,但当光强小幅增大时,随着照射时间的延长会出现小剂量效应。针对试验期间的原水,2.5mW/cm2照射6min的效果最好。经过紫外线预处理后,水的浊度略有升高,溶解氧减少,pH值降低,CODMn降低。     

Crack resistance behavior of polyvinylchloride

The effects of specimen dimension (thickness, width) and specimen configuration (SENB, CT), as well as test conditions (crosshead speed, temperature), over a range of crosshead speeds from 0.01 to 100 mm/min and temperatures from −40 to 60°C, on the crack growth resistance behavior were investigated in a commercial amorphous thermoplastic polyvinylchloride (PVC) using the J-integral and crack opening displacement (COD) concepts. With the combined application of these two different fracture mechanics parameters, more detailed information on fracture processes can be obtained. The relationship between deformation mechanisms and fracture toughness was discussed through a comparative analysis of J versus Δa and COD versus Δa resistance curves. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1079–1090, 1997     

Blends of polychloroprene and polyvinylchloride

Blends of polychloroprene rubber and plasticized polyvinylchloride have been prepared in various compositions and their properties evaluated. The properties of the blends show that they can be used to replace polychloroprene in many applications.     

Curing of crust leather by ultraviolet radiation with urethane acrylate: Role of pigment

Eight different formulations were developed with four diacrylate reactive monomers such as tripropylene glycol diacrylate (TPGDA), 1,4‐butanediol diacrylate (BDDA), 1,6‐hexanediol diacrylate (HDDA), and 2‐ethylene glycol dimethacrylate (EGDMA) and aromatic urethane diacrylate (M1100) in order to modify the crust leather surface. To study the effect of pigment on the performance of ultraviolet (UV)‐cured leather surface, 1% pigment (congored) was incorporated in the formulations. Irgacure 369 (2%) was also used in the formulation as photoinitiator. The gel content, tensile strength, elongation at break, and pendulum hardness of UV‐cured thin films with and without pigment was studied. The films without pigment produced better properties. Among all the diluents, BDDA‐containing films showed the best performance. Different properties of UV‐coated leather surface such as pendulum hardness, tensile strength, elongation, gloss (at 20° and 60°), adhesion, and abrasion were studied. Effect of gloss on simulating weathering was also performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 692–697, 2002     

Modification of cotton,rayon, and silk with urethane acrylate under ultraviolet radiation

Ten different formulations were developed with Ebcryl 264, a urethane acrylate in combination with other monofunctional monomers in the presence of some additives and coadditives. Thin films prepared from these formulations under ultraviolet (UV) radiation were characterized. Natural fibers such as cotton, rayon, and silk were treated with the formulations and cured under UV radiation. Their physical and mechanical properties were studied. It was found that the tensile strength (TS) of cotton, rayon, and silk was significantly increased as a result of this treatment under UV radiation (TS_cotton = 150%, TS_rayon = 30%, and TS_silk = 40%). Elongation of cotton and silk increased to 380 and 50%, respectively. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1703–1711, 1997     

Effect of fillers on curing of wood surfaces with polyester oligomers by ultraviolet radiation

A set of formulations was prepared with polyester acrylate (oligoester M‐9050) oligomers in combination with reactive diluents of different functionalities such as ethylhexyl acrylate, tripropylene glycol diacrylate , and trimethylol propane triacrylate (TMPTA). The thin films were prepared with these formulated solutions under UV radiation on a glass plate, and their physical properties such as pendulum hardness and gel content were studied. The formulation containing TMPTA showed the greatest pendulum hardness and gel content. The polished wood surfaces were cured with these formulated solutions. Physical properties such as pendulum hardness gloss at 20° and 60° angles, adhesion, abrasion resistance, and scratch hardness of UV‐cured surfaces of the wood were characterized. The formulation containing TMPTA had the best physical properties. Two types of filler, sand and talc, were used in the base coat to obtain these better properties. Both fillers improved the properties; however, the 1% sand– and 4% talc–containing formulations performed better. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3826–3834, 2003     

Acoustical studies on polyvinylchloride in dimethylformamide

Ultrasonic velocity studies were undertaken on solutions of polyvinylchloride (PVC) in dimethylformamide (DMF) in the concentration range 0–3% by weight, at an RF frequency of 2 MHz at three different temperatures, 303 K, 313 K and 323 K. The observed non-linear increase in ultrasonic velocity with increase of PVC concentration is attributed to the segment–segment interaction which causes molecular association between PVC and DMF.     

Dielectric depolarization spectra of toughened polyvinylchloride

Toughened PVC systems prepared on the basis of Hostalit H-9970 (Hoechst AG) were studied by dielectric depolarization spectroscopy. The spectra obtained as a function of the temperature were compared with dynamic mechanical and dielectric relaxation spectra and with thermomechanical curves. The dielectric depolarization peaks were found to correlate with the structural transitions measured by mechanical and dielectric spectroscopy.     

Curing of composite components by ultraviolet radiation: A review

Curing of polymer matrices by ultraviolet (UV) irradiation can be applied to a variety of processes in the production of composite components, as long as the component can be directly irradiated. Wet lay‐up techniques, vacuum infusion type processes with UV‐transparent membranes, filament winding, and prepreg processes have been adapted to UV curing. Unlike in thermal curing, the curing time is in the order of magnitude of minutes rather than hours, which means a significant reduction in cycle time. The radiation can be generated by a variety of sources suitable for various specific applications and different curing strategies. The most frequently used radiation sources are mercury arc lamps. Because of the absorption of radiation passing through matter, the thickness of laminates for efficient application of UV curing is limited. The curing mechanism is either radical polymerization for acrylate‐based resins or cationic polymerization for epoxies and vinyl ethers. The properties of the UV‐cured polymer matrix are determined by the cross‐linking density. This depends on the type and concentration of the photoinitiator and of the (optional) diluents, the intensity and the duration of the irradiation, and the temperature at which the curing process takes place. POLYM. COMPOS., 27:119–128, 2006. © 2006 Society of Plastics Engineers.     

The effect of ultraviolet radiation on chemically crosslinked low-density polyethylene

Tensile properties of UV-irradiated thermoplastic and crosslinked low-density polyethylene were studied as function of the irradiation time, degree of crosslinking, and the presence of a UV stabilizer. Well-crosslinked samples (about 70% gel) and UV-stabilized are shown to be of superior weathering resistance. Crosslinking by itself results in an insignificant improvement which is much less than the effect of UV stabilization of the noncrosslinked polymer. The combination of crosslinking/UV stabilization produces samples of significant resistance to UV irradiation.     

Interfacial (polymer-substrate) failure of ultraviolet radiation curable coatings

The development of ultraviolet radiation technology to cure or photopolymerize acrylic unsaturated monomers, oligomers, and polymers into tight network structures introduces several adhesion problems that can be related to or associated with interfacial polymer-substrate failure. This paper discusses network formation, polymer-interfacial growth association and failure as a function of the following variables: light intensity (effect on sol/gel conversion), photoinitiator (structurereactivity as a function of conversion), polymer shrinkage, and substrate wetting. The results of this study show that all of the above variables interact in a composite fashion to influence the final properties of the ultraviolet cured coatings.     

A comparative study of gamma and ultraviolet radiation on gelatin film with 2-ethylhexyl acrylate

Gelatin films were prepared from gelatin granules in an aqueous medium by casting. Tensile strength (TS) and elongation at break (Eb%) of the films were found to be 29.2?MPa and 4.9%, respectively. Gelatin films were irradiated under gamma and UV radiation with different doses. Gamma treated gelatin films showed higher TS and Eb% over untreated ones, and even higher than that of the UV treated films. A series of gelatin solutions (formulations) was prepared by blending varying percentages (2–10% by wt) of 2-ethylhexyl acrylate (EHA) and then the films were prepared. Some EHA-blended gelatin films were irradiated under gamma radiation at various doses (50–500?krad) and other films were cured under UV radiation at different intensities (10–30 UV passes). EHA-blended?+?gamma treated gelatin films showed the highest mechanical properties than that of the EHA-blended?+?UV treated films. The degradation properties present in the soil were determined for the pure and treated films. It was observed that EHA-blended?+?gamma treated gelatin film degrades more than that of the EHA-blended?+?UV treated films.     

Improvement of properties of natural polymers with organo–metallic complexes under ultraviolet radiation

Thin polymer films were prepared under ultraviolet radiation with a triacrylated aliphatic urethane oligomer that was diluted with reactive monomers such as N‐vinyl pyrrolidone and tripropylene glycol diacrylate. These films were characterized. The effect of incorporation of a minute amount (>0.15%) of a titanium–pyridine complex and its ligands on the characterization of these polymers was investigated. Cotton and jute yarns were treated with the solutions containing these materials under the UV radiation. The change in tensile properties of the treated natural polymers (cotton and jute) was evaluated, and it was found that the titanium–pyridine‐based complex substantially enhanced the tensile strengths (tenacity) for both cotton and jute. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1131–1138, 1999     

Abnormal structures in polyvinylchloride I—A method of estimating labile chloride groups in polyvinylchloride

An attempt has been made to estimate the amount of allylic chloride and tertiary chloride structures present in polyvinylchloride. Preliminary work using 2,4-dichloropentane, 4-chlorohexene-2, and 3-ethyl-3′-chloropentane as model compounds with secondary chloride, allylic chloride and tertiary chloride structures, has shown appreciable differences in the reactivity of these groups towards metal acetates in ester exchange reactions. The addition of a second component such as pyridine or epichlorhydrin was found to be necessary to produce a stable ester structure. Procedures have been devised for estimating allylic chlorides and tertiary chlorides present in polyvinylchloride based on results with model compounds. The extent of chloride replacement by acetate has been determined from the i.r. absorption at 1720 cm⁻¹. Support for the procedures adopted has been obtained from work with alkali-treated PVC and chlorinated alkali-treated PVC, and although the method is not yet quantitative, an indication of the relative proportions of allylic and tertiary chloride structures present in polyvinylchloride can be obtained. Results with fractionated commercial PVC indicate that the higher molecular weight fractions contain largely tertiary chloride structures whereas the lower molecular weight fractions contain more allylic chloride groups.