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51.
Polypropylene/poly(butyl methacrylate)(PP/PBMA) blends were prepared by diffusion and subsequent polymerization of butyl methacrylate(BMA) in commercial isotactic polypropylene(iPP) pellets.The diffusion kinetics,diametrical distribution of PBMA in a pellet and phase morphology of a typical PP/PBMA blend were investigated. 相似文献
52.
Tomohiro Hirano Kousuke Higashi Makiko Seno Tsuneyuki Sato 《Journal of polymer science. Part A, Polymer chemistry》2004,42(19):4895-4905
We have reported that intramolecular chain‐transfer reaction takes place in radical polymerization of itaconates at high temperatures and/or at low monomer concentrations. In this article, radical polymerizations of di‐n‐butyl itaconate (DBI) were carried out in toluene at 60 °C in the presence of amide compounds. The 13C‐NMR spectra of the obtained poly(DBI)s indicated that the intramolecular chain‐transfer reaction was suppressed as compared with in the absence of amide compounds. The NMR analysis of DBI and N‐ethylacetamide demonstrated both 1:1 complex and 1:2 complex were formed at 60 °C through a hydrogen‐bonding interaction. The ESR analysis of radical polymerization of diisopropyl itaconate (DiPI) was conducted in addition to the NMR analysis of the obtained poly(DiPI). It was suggested that the suppression of the intramolecular chain‐transfer reaction with the hydrogen‐bonding interaction was achieved by controlling the conformation of the side chain at the penultimate monomeric unit of the propagating radical with an isotactic stereosequence. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4895–4905, 2004 相似文献
53.
Gang Feng Yongguang Jia Lingyan Liu Weixing Chang Jing Li 《Journal of polymer science. Part A, Polymer chemistry》2010,48(24):5992-6002
A series of novel organotin‐containing core‐cross‐linked knedels and shell‐cross‐linked knedels were first synthesized facilely from poly(styrene)‐b‐poly(acrylate acid) nanoparticles in different selective solvents [Tetrahydrofuran (THF)/H2O or THF/n‐octane] by using organotin compound 1,3‐dichloro‐tetra‐n‐butyl‐distannoxane as a new cross‐linker. The formation of the 1‐chloro‐3‐carboxylato‐tetra‐n‐butyl‐distannoxane layer in our cross‐linking reaction was supported by Fourier transform infrared (FT‐IR) and inductive coupled plasma emission spectrometer (ICP) analysis of the resulting shell‐cross‐linked knedels and core‐cross‐linked knedels. Transmission electron microscopy (TEM) study showed the spherical morphology and the size of the core‐cross‐linked knedels and shell‐cross‐linked knedel. Especially, the layer structure of the core‐cross‐linked knedels was clearly displayed in TEM image. The increase of extent of cross‐linking lead to the increasing of diameter for the shell‐cross‐linked knedels, whereas there was no significant effect on the core‐cross‐linked knedels. Dynamic light scattering (DLS) measurements gave hydrodynamic diameters of the core‐cross‐linked knedels that were in agreement with the TEM diameters. Moreover, the wall thickness of the shell layer of the core‐cross‐linked knedels could be easily modified by varying the block copolymer composition. Notably, the organotin‐containing core‐cross‐linked knedel exhibited highly efficient catalytic activity for the aqueous esterification reaction under nearly neutral conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
54.
对甲苯磺酸催化合成乙酸正丁酯 总被引:8,自引:0,他引:8
用对甲苯磺酸作冰乙酸和正丁醇的酯化催化剂,成功地合成了乙酸正丁酯,考察了影响反应的因素,探讨并找到了较好的反应条件:乙酸l00mmol,n(冰乙酸):n(正丁醇):n(催化剂)=1:3:0.006,反应时间1.5h,不另加带水剂,产率达99.14%。 相似文献
55.
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57.
Structures of tert-butylcarbamate ions in the gas-phase and methanol solution were studied for simple secondary and tertiary carbamates as well as for carbamate-containing products and internal standards for lysosomal enzyme assays used in newborn screening of a α-galactosidase A deficiency (Fabry disease), mucopolysaccharidosis I (Hurler disease), and mucopolysaccharidosis II (Hunter disease). The protonation of simple t-butylcarbamates can occur at the carbonyl group, which is the preferred site in the gas phase. Protonation in methanol solution is more favorable if occurring at the carbamate nitrogen atom. The protonation of more complex t-butylcarbamates occurs at amide and carbamate carbonyl groups, and the ions are stabilized by intramolecular hydrogen bonding, which is affected by solvation. Tertiary carbamates containing aminophenol amide groups were calculated to have substantially greater gas-phase basicities than secondary carbamates containing coumarin amide groups. The main diagnostically important ion dissociation by elimination of 2-methylpropene (isobutylene, i-C(4)H(8)) and carbon dioxide is shown by experiment and theory to proceed in two steps. Energy-resolved collision-induced dissociation of the Hurler's disease enzymatic product ion, which is a coumarin-diamine linker-t-butylcarbamate conjugate (3a(+)), indicated separate energy thresholds for the loss of i-C(4)H(8) and CO(2). Computational investigation of the potential energy surface along two presumed reaction pathways indicated kinetic preference for the migration of a t-butyl hydrogen atom to the carbamate carbonyl resulting in the isobutylene loss. The consequent loss of CO(2) required further proton migrations that had to overcome energy barriers. 相似文献
58.
The on-line detection of emulsion polymerization processes by means of solid-state NMR spectroscopy is demonstrated for the
first time using poly(butyl acrylate) as a model system. Relatively short time intervals are accessible via 1H detection while the use of 13C NMR spectroscopy results in an increased spectral resolution. Details of sample preparation and experimental techniques
are given, while remaining artifacts of the preliminary results will be addressed in further investigations.
Received: 7 November 1997 Accepted: 5 January 1998 相似文献
59.
IntroductionFreeradicalformationfromhalogenatedhydrocarbonshasreceivedconsiderableattentionbecauseofitsscientif icandenvironmentalrelevance .1 6 Thisreactionseemstoplayanimportantroleinvariousprocesses .Bond break ingreactionisapowerfulsynthetictooltoprov… 相似文献
60.
Darwin P. R. Kint Antxon Martínez de Ilarduya Abdelilah Alla Sebastin Muoz‐Guerra 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):124-134
Poly(ethylene terephthalate‐co‐isophthalate‐co‐5‐tert‐butylisophthalate) (PETItBI) terpolymers were investigated with reference to poly(ethylene terephthalate) (PET) homopolymer and poly(ethylene terephthalate‐co‐isophthalate) (PETI) copolymers. Three series of PETItBI terpolyesters, characterized by terephthalate contents of 90, 80, and 60 mol %, respectively, with different isophthalate/5‐tert‐butylisophthalate molar ratios, were prepared from ethylene glycol and mixtures of dimethyl terephthalate, dimethyl isophthalate, and 5‐tert‐butylisophthalic acid. The composition of the terpolymers and the composition of the feed agreed. All terpolymers had a random microstructure and number‐average molecular weights ranging from 10,000 to 20,000. The PETItBI terpolyesters displayed a higher glass‐transition temperature and a lower melting temperature than the PETI copolymers having the same content of terephthalic units. Thermal stability appeared essentially unchanged upon the incorporation of the 5‐tert‐butylisophthalic units. The PETItBIs were crystalline for terephthalate contents higher than 80 mol %, and they crystallized at lower rates than PETI. The crystal structure of the crystalline terpolymers was the same as that of PET with the 1,3‐phenylene units being excluded from the crystalline phase. Incorporation of isophthalate comonomers barely affected the tensile modulus and strength of PET, but the brittleness of the terpolymers decreased for higher contents in 5‐tert‐butylisophthalic units. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 124–134, 2003 相似文献