Synthesis of dodecenyl succinic anhydride (DDSA) corn starch

Dodecenly succinic anhydride (DDSA) starches were prepared commercially by the base catalyzed reaction of DDSA in pre-emulsion with starch granular in aqueous slurry. The results indicated that the degree of substitution and reaction efficiency were 0.0256% and 42.7%, respectively, at the parameters for the preparation of DDSA starches in starch slurry 30%, DDSA/starch radio 10% (wt/wt), pH 8.5-9.0, reaction temperature 313 K. After modification, product surface chemical composite had been changed which was prone to migrate into less polar solution. The chemical structural characteristics were investigated by methods of FTIR and H-1 NMR. The results of X-ray diffraction showed the native A-type crystalline pattern, indicating that reaction of corn starch with DDSA caused no change in the crystalline structure. Compared to native starch, the hydrophobic performance of esters was greatly increased. With the DS increasing, contact angles were gradually increased, however, the adhesion works were decreased. The maximum contact angle of DDSA starch could attend to 123 degrees, and the corresponding adhesion work was 33.2 mJ m(-2).

Modificação da pasta kraft de eucalipto para novas aplicações

Este trabalho constou num estudo da modificação da pasta kraft de eucalipto, utilizando uma técnica de processamento por alta pressão hidrostática com o intuito de melhorar a sua performance para novas aplicações tal como o papel tissue ou o papel para embalagens. Para tal pretendia-se melhorar algumas propriedades da pasta com a utilização da técnica de alta pressão hidrostática. Realizou-se um estudo preliminar onde se submeteu uma pasta branqueada A, não refinada, a um tratamento hiperbárico (TH) numa gama de pressões de 5000-8000 bar. Para uma pressão de 6000 bar constatou-se uma melhoria de cerca de 16 % no alongamento percentual na rotura, 17 % na resistência à tração, 27 % no índice de rebentamento e cerca de 19 % no índice de rasgamento. Posteriormente, e tendo em conta os resultados positivos verificados na pasta A, estudou-se o efeito do TH numa pasta branqueada B variando a consistência de tratamento (1,5% ou 3%) e o tempo de processamento (5 ou 10 minutos). Foi estudado também o efeito do TH quando aplicado antes e após a refinação da pasta. A pasta branca foi submetida à refinação num moinho PFI entre 1000 e 3000 rotações. Os resultados obtidos mostram que o TH realizado a menores consistências apresenta um efeito mais significativo nas propriedades físico-mecânicas de pastas e que o efeito é distinto quando o processamento é aplicado antes e depois da refinação, tendo-se registado melhoramentos das propriedades mecânicas apenas quando o TH ocorre após a refinação. A pasta kraft foi também modificada com anidrido alquenil succínico (ASA). A modificação da pasta de celulose com ASA resultou numa diminuição das propriedades mecânicas e para além disso não gerou qualquer alteração na termoplasticidade do material, no entanto registou-se um aumento na resistência à molhabilidade. Concluiu-se que o TH conduz a alterações ao nível de propriedades mecânicas e estruturais da pasta de interesse para a aplicação em papéis tissue no caso da pasta B. Para além disso a modificação da pasta com ASA resultou em alterações de interesse particular para papéis de embalagem.

Selective hydrogenation of maleic anhydride to gamma-butyrolactone in supercritical carbon dioxide

The reaction rates of the hydrogenation of maleic anhydride (MAH) and succinic anhydride (SAH) were significantly accelerated and the selectivity to gamma-butyrolactone (GBL) was enhanced largely when the reaction mixture was pressurized by a non-reactant of CO2. Above 99% selectivity to GBL was achieved in 14 MPa CO2, the superior selectivity in scCO(2) was attributed to that MAH and/or SAH could be extracted to CO2 phase and separated from H2O, the hydrolysis were thus minimized and so the selectivity to GBL was improved.

Carbodiimide-mediated synthesis of poly(L-lactide)-based networks

Poly(L-lactide-co-succinic anhydride) networks were synthesised via the carbodiimide-mediated coupling of poly(L-lactide) (PLLA) star polymers. When 4-(dimethylamino)pyridine (DMAP) alone was used as the catalyst gelation did not occur. However, when 4-(dimethylamino)pyridinium p-toluenesulfonate (DPTS), the salt of DMAP and p-toluenesulfonic acid (PTSA), was the catalyst, the networks obtained had gel fractions comparable to those which were reported for networks synthesised by conventional methods. Greater gel fractions and conversion of the prepolymer terminal hydroxyl groups were observed when the hydroxyl-terminated star prepolymers reacted with succinic anhydride in a one-pot procedure than when the hydroxyl-terminated star prepolymers reacted with presynthesised succinic-terminated star prepolymers. The thermal properties of the networks, glass transition temperature (Tg), melting temperature (Tm) and crystallinity (Xc) were all strongly influenced by the average molecular weights between the crosslinks ((M_c). The network with the smallest (M_c )(1400 g/mol) was amorphous and had a Tg of 59 °C while the network with the largest (M_c ) (7800 g/mol) was 15 % crystalline and had a Tg of 56 °C.

Photochromic fulgide for holographic recording

(N-4'-methoxy-2-methyl-5-phenyl)-3-pyrryl-ethylidene (isopropylidene) succinic anhydride fulgide, doped in PMMA matrix, exhibits photochromic behavior. The fatigue resistance experiment shows no photodegradation is detected after more than 450 writing-erasing cycles. Study of fulgide material for holographic recording media shows the optimal exposure and the diffraction efficiency is 1047 mJ/cm(2) and 2.26%, respectively, with 10 mum thickness polymer film. Holographic grating with 1680 lines/mm at writing angle theta = 30degrees is also obtained. (C) 2004 Elsevier B.V. All rights reserved.

Synthesis, self-assembly in water, and cytotoxicity of MPEG-block-PLLA/DX conjugates

Docetaxel (DX) is one of the most effective antineoplastic drugs. Its current clinical administration is limited because of its hydrophobicity and Serious side effects. A polymer/DX conjugate is designed and successfully prepared to solve these problems. It is monomethoxy-poly(ethylene glycol)-block-poly(L-lactide)/DX (MPEG-PLLA/DX) It was synthesized by reacting DX with carboxyl-terminated copolymer MPEG-PLLA, which was prepared by reacting succinic anhydride with hydroxyl-terminated copolymer monomethoxy-poly(ethylene glycol)-block-poly (L-lactide) (MPEG-PLLA). Its structure and molecular weight was confirmed by H-1 NMR and GPC. The MPEG-PLLA/DX micelles in aqueous solution were prepared Using a SO]vent displacement method and characterized by dynamic light scattering for size and size distribution, and by transmission electron microscopy for surface morphology. Its antitumor activity against HeLa cancer cells evaluated by MTT assay showed that it had a similar antitumor activity to Pure D at the same drug content.

Synthesis of novel functional polyolefin containing carboxylic acid via Friedel-Crafts acylation reaction

The strong polar group, carboxylic acid, has triumphantly been introduced into ethylene and allylbenzene copolymers without obvious degradation or crosslinking via Friedel-Crafts (F-C) acylation reaction with glutaric anhydride (GA), succinic anhydride (SA) and phthalic anhydride (PA) in the presence of anhydrous aluminum chloride in carbon disulfide. Some important reaction parameters were examined in order to optimize the acylation process. In the optimum reaction conditions, almost all of the phenyls can be acylated with any anhydride. The microstructure of acylated copolymer was characterized by Fr-IR, H-1 NMR and H-1-H-1 COSY. All the peaks of acylated copolymers can be accurately attributed, which indicates that all the acylation reactions occur only at the para-positions of the substituent of the aromatic rings. The thermal behavior was studied by differential scanning calorimetry (DSC), showing that the melting temperatures (T(m)s) of acylated copolymers with GA firstly decrease slowly and then increase significantly with the increase of the amount of carboxyl acid groups.

Triblock poly(lactic acid)-b-poly(ethylene glycol)-b-poly(lactic acid)/paclitaxel conjugates: Synthesis, micellization, and cytotoxicity

A triblock poly(lactic acid)-b-poly(ethylene glycol)-b-poly(lactic acid) (PLA-PEG-PLA)/paclitaxel (PTX) conjugate was synthesized by the reaction of carboxyl-terminated copolymer PLA-PEG-PLA with PTX in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine. Carboxyl-terminated copolymer PLA-PEG-PLA was prepared by the reaction of the hydroxyl end groups in copolymer PLA-PEG-PLA with succinic anhydride. Its structure was confirmed by NMR and gel permeation chromatography. The PLA-PEG-PLA/PTX conjugates could self-assemble into micelles in aqueous solutions with a low critical micelle concentration. Dynamic light scattering and environmental scanning electron microscopy analyses of the PLA-PEG-PLA/PTX micelles revealed their spherical structure and size of 220 nm. The antitumor activity of the conjugate against woman Hela cancer cells, evaluated by the 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyl tetrazolium bromide method, showed that the conjugates had an antitumor activity similar to that of pure PTX. The obtained PLA-PEG-PLA/PTX conjugates are expected to be used in clinical practice.

Removal of Zn(2+) from Electroplating Wastewater Using Modified Wood Sawdust and Sugarcane Bagasse

This paper describes the preparation of new adsorbents derived from sugarcane bagasse and wood sawdust (Manilkara sp.) to remove zinc (II) ions from electroplating wastewater. The first part deals with the chemical modification of sugarcane bagasse and wood sawdust, using succinic anhydride to introduce carboxylic acid functions into the material. The obtained materials (modified sugarcane bagasse MB2 and modified wood sawdust MS2) were then characterized by infrared spectroscopy (IR) and used in adsorption experiments. The adsorption experiments evaluates Zn(2+) removal from aqueous single metal solution and real electroplating wastewater on both batch and continuous experiments using fixed-bed columns prepared in laboratorial scale with the obtained adsorbents. Adsorption isotherms were then developed using Langmuir model and the Thomas kinetic model. The calculated Zn(2+) adsorption capacities were found to be 145 mg/g for MS2 and 125 mg/g for MB2 in single metal aqueous solution, whereas for the industrial wastewater these values were 61 mg/g for MS2 and 55 mg/g for MB2.

Application of succinylated sugarcane bagasse as adsorbent to remove methylene blue and gentian violet from aqueous solutions - Kinetic and equilibrium studies

In a previous work, succinylated sugarcane bagasse (SCB 2) was prepared from sugarcane bagasse (B) using succinic anhydride as modifying agent. In this work the adsorption of cationic dyes onto SCB 2 from aqueous solutions was investigated. Methylene blue, MB, and gentian violet, GV, were selected as adsorbates. The capacity of SCB 2 to adsorb MB and GV from aqueous single dye solutions was evaluated at different contact times, pH, and initial adsorbent concentration. According to the obtained results, the adsorption processes could be described by the pseudo-second-order kinetic model. Adsorption isotherms were well fitted by Langmuir model. Maximum adsorption capacities for MB and GV onto SCB 2 were found to be 478.5 and 1273.2 mg/g, respectively. (C) 2011 Elsevier Ltd. All rights reserved.

Manufacturing DNA microarrays of high spot homogeneity and reduced background signal

Analyses on DNA microarrays depend considerably on spot quality and a low background signal of the glass support. By using betaine as an additive to a spotting solution made of saline sodium citrate, both the binding efficiency of spotted PCR products and the homogeneity of the DNA spots is improved significantly on aminated surfaces such as glass slides coated with the widely used poly-l-lysine or aminosilane. In addition, non-specific background signal is markedly diminished. Concomitantly, during the arraying procedure, the betaine reduces evaporation from the microtitre dish wells, which hold the PCR products. Subsequent blocking of the chip surface with succinic anhydride was improved considerably in the presence of the non-polar, non-aqueous solvent 1,2-dichloroethane and the acylating catalyst N-methylimidazole. This procedure prevents the overall background signal that occurs with the frequently applied aqueous solvent 1-methyl-2-pyrrolidone in borate buffer because of DNA that re-dissolves from spots during the blocking process, only to bind again across the entire glass surface.

Synthesis and characterization of photochromic indolyl substituted fulgides and fulgimides

The fulgide and fulgimide family constitutes an important class of organic photochromic compounds. The ability of fulgides and fulgimides to interconvert between two key forms by irradiation of different wavelength of light has made them promising material in optical memory devices, optical switches and sensors, and specialty dyes and inks. Thermal stability and hydrolytic stability of fulgides and fulgimides are essential for their practical applications. A deuterated trifluoromethyl indolylfulgide was synthesized based on the synthetic pathway of the proteo trifluoromethyl indolylfulgide using commercially available deuterated starting materials. Deuteration of the isopropylidene group improved the thermal stability of the indolylfulgide by a factor of 7. ^ Fulgimides are the most important fulgide derivatives. Fulgimides improve the hydrolytic stability of fulgides by replacing the succinic anhydride ring with a succinimide ring. A novel trifluoromethyl N-ethoxycarbonylmethyl indolylfulgimide was synthesized from trifluoromethyl indolylfulgide. The trifluoromethyl indolylfulgide was synthesized on a large scale in five steps with an overall yield of 18%. The indolylfulgide was then converted to indolylfulgimide by aminolysis follow by dehydration. The N-ethoxycarbonylmethyl indolylfulgimide showed enhanced hydrolytic stability and photochemical stability in 70/30 ethanol/water. ^ Three novel aqueous soluble fulgimides, trifluoromethyl carboxylic acid indolylfulgimide, dicarboxylic acid indolylfulgimide, and H-carboxylic acid indolylfulgimide, were synthesized. In sodium phosphate buffer (pH 7.4) at 37 ºC, an unusual hydrolysis of the trifluoromethyl group of the closed form of the carboxylic acid indolylfulgimide resulted in the dicarboxylic acid indolylfulgimide which has an additional carboxylic acid group. The closed form of dicarboxylic acid indolylfulgimide was further decarboxylated to generate H-carboxylic acid indolylfulgimide which was not photochromic. The trifluoromethyl dicarboxylic acid indolylfulgimide is the most robust fulgimide yet reported in aqueous solution. ^ A novel aqueous soluble methyl carboxylic acid indolylfulgimide was synthesized from methyl indolylfulgide. The methyl indolylfulgide was synthesized in five steps with an overall yield of 21%. The methyl carboxylic acid indolylfulgimide was synthesized by aminolysis follow by dehydration. The methyl carboxylic acid indolylfulgimide is expected to have improved thermal and photochemical stability in aqueous solutions relative to the trifluoromethyl analog.^

Hyperbranched polymers containing oxazoline monomers andsuccinic anhydride: applications in fast drying, low solvent coating formulations

tMelt-polycondensation of succinic acid anhydride with oxazoline-based diol monomers gave hyper-branched polymers with carboxylicacids terminal groups.1H NMR and quantitative13C NMRspectroscopy coupled with DEPT-13513C NMR experiment showed high degrees of branching (over 60%).Esterification of the acid end groups by addition of citronellol at 160◦C produced novel white spirit solubleresins which were characterized by Fourier transform-infrared (FTIR) spectroscopy, gel permeation chro-matography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Blendsof the new hyperbranched materials with commercial alkyd resins resulted in a dramatic, concentrationdependent drop in viscosity. Solvent-borne coatings were formulated containing the hyperbranchedpolymers. Dynamic mechanical analysis studies revealed that the air drying rates of the new coatingsystems were enhanced compared with identical formulations containing only commercial alkyd resins.