Study of the Interfacial Reaction of Styrene/Maleic Anhydride Copolymerand (Amine)-Terminated Butadiene-Acrylonitrile Copolymer Using FTIR Imaging Techniques

The interfacial reaction between styrene/maleic anhydride copolymer (SMA) and amine-terminated butadiene-acrylonitrile copolymer (ATBA) was observed using Fourier transform infrared (FTIR) imaging spectroscopy. The anhydride and amine reacted to form an imide. Each component was detected using a characteristic wavenumber, which was 1601 cm ?1 for SMA, 2237 cm ?1 for ATBA, and 1701 cm ?1 for the imide. FTIR images were taken as the reaction proceeded at 150, 160, 170, and 180°C. At low temperatures (150 and 160°C), diffusion-controlled kinetics were observed since interdiffusion between the reactants did not appear in the images. On the other hand, both the diffusion front and the reaction front are observed in the images at high reaction temperatures (170 and 180°C), which indicates that the kinetics became reaction-controlled rather than diffusion-controlled. Absorbance profiles were extracted from the images and used for the calculation of the extent of reaction. The data were analyzed using the Frederickson and Milner theory based on the assumption of diffusion-controlled kinetics, and this theory fit the low reaction temperature data.     

Amidification of poly(styrene-co-maleic anhydride) with amines in tetrahydrofuran solution: A kinetic study

Summary The kinetics of the reaction between a styrene-maleic anhydride copolymer (SMA) and amines was investigated in tetrahydrofuran solution between 0°C and 40°C. This reaction converts the maleic anhydride (MA) into the corresponding amide-acid, while the consecutive reaction of the generated acid with amine forming a diamide or transformation of the acid-amide into the imide was not observed. The amine reactivity follows the order: 1-octylamine> >1-methyl hexylamine> >1,1-dimethyl propylamine or dibutylamine, demonstrating that the amine reactivity depends, to a large extent, upon its steric hindrance. This reaction is reversible as shown by IR at high temperatures, but the reverse reaction was undetectable between 0 and 40°C. The overall reaction involves spontaneous and autocatalytic reactions, and the overall reaction rate can be written as:-d[MA]/dt=k₀[MA][-NH₂]+k₁[MA][-NH₀]². In the case of 1-octylamine below 0.02 M, the spontaneous reaction dominates (i.e, k₀> >k₁[-NH₂]).     

Polymer blends with modified coupling agent. I. Preparation and thermal properties of LICA 44 grafted styrene–maleic anhydride copolymer

Neopentyl(diallyl)oxy, tri(N-ethyleneamino)ethyl titanate (LICA 44) was grafted to the styrene/maleic anhydride (SMA) copolymer for the purpose of obtaining a new interfacial coupling agent for flame retardant ABS blends. The graft reaction was proceeded in DMSO under 80°C and reduced pressure. Samples were prepared under various amine/anhydride ratios (AAR) in feed and reaction time. The verification of reaction was based on FTIR spectra and the results of elemental analysis. The reaction percentages were high but decreased with the rising AAR. Both combination types, amide acid and imide, of SMA and LICA 44 were found, and the ratio of amide acid and imide is related to the AAR and reaction time. After the graft reaction, both the initial pyrolysis temperature (T_pi) and the char yield at 800°C of SMA increased significantly. LICA 44 is believed to cause the char promoting effect on SMA-g-L44. And the dealcohol phenomenon of trimethylolpropane diallyl ether (TMPDE) away from SMA-g-L44 was observed during the thermal analysis. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:37–44, 1998     

Thermal crosslinking of poly(methyl methacrylate-co-N,N-dimethylaminopropylacrylamide)

Summary Copolymers of methyl methacrylate(MMA) with N,N-dimethylaminopropylacrylamide (DMA) were heated at various temperatures, and their thermal crosslinking was investigated. A copolymer with a compsition of [MMA]/[DMA] =3 became completely insoluble in chloroform when heated at 180°C for 5 minutes or at 150°C for 20 minutes. Other copolymers containing less than 5 mol % DNA also crosslinked when heated at 170°C for 30 minutes. A mixture of polyMMA with N,N-dimethylaminopropylbenzamide also crosslinked when heated at 170°C. A copolymer of styrene with DMA also crosslinked when heated at above 140°C although the crosslinking was much slower than that of poly(MMA-co-DMA). The formation of imide linkages is proposed as the crosslinking mechanism.     

Kinetic aspects of the formation of lead zirconium titanate

The kinetics of the second calcination step in the formation of PZT solid solution (with perovskite ABO₃ lattice) has been investigated by using two different particle sizes of the B-site precursor (1.91 and 5.08 μm), the finer size being obtained by prolonged milling. In-situ analysis performed by high-temperature X-ray diffractometry in a non-isothermal mode (20–800 °C) revealed a reduction of the calcination temperature by 100 °C with a decrease in particle size of the precursor. In order to clarify the mechanism of the solid-state reaction to PZT, isothermal heat treatment of the mixtures was performed in the temperature range 540–700 °C. The activation energies for the fine and the coarse powders were estimated as 150 and 210 kJ mol⁻¹ respectively, and the reaction was found to follow the Jander model for diffusion-controlled solid-state reaction kinetics.     

Synthesis of styrene–maleic anhydride random copolymer and its compatibilization to poly(2,6‐dimethyl‐1,4‐phenylene ether)/brominated epoxy resin

Styrene–maleic anhydride random copolymer (R‐SMA_7.5), with a low content of maleic anhydride (MAH) of about 7.5 mol%, has been prepared, and the copolymer was characterized by fourier‐transform infrared (FTIR) and ¹³C NMR techniques showing that the product contained only random copolymer without blocks. The miscibility between poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE) and R‐SMA, was investigated by differential scanning calorimetry (DSC), showing that PPE was miscible with R‐SMA synthesized in our laboratory over the entire composition with low MAH content. A blend of R‐SMA₁₈ (MAH content is about 18 mol%) and PPE was also studied by DSC, which showed that PPE was immiscible when R‐SMA was the major component, although it was miscible with limited composition. FTIR investigation showed that R‐SMA could react with bromide epoxy (BEP) resin at high temperature (180°). The heat‐resistance and mechanical properties of R‐SMA/PPE/BEP systems were tested and analyzed, and results indicated that R‐SMA could improve the miscibility of PPE and BEP with increasing T_g of the BEP phase and decreasing the T_g of the PPE slightly, improving the breaking elongation and breaking energy, which resulted from good miscibility between PPE and BEP with R‐SMA as the compatibilizer. Finally, the properties of the composites (copper clad laminate) with R‐SMA_7.5 are studied and discussed. Copyright © 2003 Society of Chemical Industry     

Poly(styrene-alt-maleic anhydride)-4-aminophenol conjugate: synthesis and antibacterial activity

Poly(styrene-alt-maleic anhydride) (SMA) may be conveniently used as an intermediate in preparing functional polymers since active agents containing amino or hydroxy groups can be linked to it via ring-opening reaction. In this study, SMA was reacted with 4-aminophenol (AP) to obtain SMA–AP conjugate. The glass transition temperature (218 °C) of the polymer was higher than that of SMA (202 °C) due to intermolecular hydrogen bonding. The polymer underwent thermal degradation in two steps where the initial weight loss began to occur at about 230 °C due to the formation of acid anhydride bonds with loss of water. SMA-AP exhibited bactericidal activity against E. coli and S. aureus, but it did not show any inhibition zone against the bacteria cells. No free AP was detected from the polymer incubated under similar conditions. Therefore, it was concluded that SMA–AP may be a bactericidal material by itself and its bactericidal activity may last for a fairly long period of time under neutral conditions.     

Study of Reaction Between a Low Molecular Weight,Highly Functionalized Polyethylene and Hexamethylenediamine

Reactions were carried out between a low molecular weight, highly functionalized maleic anhydride‐grafted polyethylene and hexamethylenediamine in a melt blender at 150 °C for various stoichiometric ratios of functional groups. For all compositions, two peaks were observed in the mixing torque data. The appearance of the first peak, observed soon after the introduction of the reactive mixture to the melt blender, was independent of composition. The second peak was composition‐dependent. Gel content and FTIR analyses suggest that the first peak is a result of melting functionalized polyethylene and a reaction of the anhydride and amine functionalities, while the second was mainly a result of crosslinking. The time between the first and second peak defines a processing window, in which the reaction mixture is thermoplastic. Higher temperature melt processing of the thermoplastic reaction products converted these materials to thermosets. During this conversion, the progress of the anhydride–amine reaction was studied using FTIR, as well as by measuring the generation of the insoluble crosslinked material. The FTIR results reveal that the reaction between anhydride and amine moieties results in the formation of an amide intermediate, which then converts to cyclic imide at higher temperatures. The analysis suggests that the use of the FTIR anhydride absorption to assess the degree of reaction is misleading in these reactions.

     

Nuclear magnetic resonance studies of selectively deuterated aromatic liquid crystalline copolyesters

Deuterium n.m.r. has been used to follow the molecular dynamics of three polyester materials over a temperature range of −150°C to 150°C. Two of the materials are liquid crystalline copolymers, one of perdeuterated hydroxybenzoic acid and hydroxynaphthoic acid and the other of hydroxybenzoic acid, isophthalic acid and perdeuterated hydroquinone. The third sample is crystalline poly(ethylene terephthalate) (PET) in which the benzene rings are deuterated. At the lowest temperatures examined all three materials give n.m.r. lineshapes characteristic of little molecular motion. On heating the liquid crystalline materials, the onset of motion is observed, first in the form of 180^o flips and then unrestricted rotation about the polymer axes. The PET spectra show a small degree of 180^o ring flipping to be taking place above 100°C, but most of the motion is in the form of near random motion that comes to dominate at 150°C. The results confirm the relatively stiff rod-like nature of the liquid crystalline polymers in comparison to the more flexible PET.     

Effect of poly(styrene‐co‐maleic anhydride) imidization on the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride)/poly(vinyl methyl ether) and poly(styrene‐co‐maleic anhydride)/ poly(methyl methacrylate) blends

The objective of this work was to study the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride) (SMA)/poly(vinyl methyl ether) (PVME) and SMA/poly(methyl methacrylate) (PMMA) blends with differential scanning calorimetry and small‐angle light scattering techniques. We focused on the effect of SMA partial imidization with aniline on the miscibility and phase‐separation temperatures of these blends. The SMA imidization reaction led to a partially imidized styrene N‐phenyl succinimide copolymer (SMI) with a degree of conversion of 49% and a decomposition temperature higher than that of SMA by about 20°C. We observed that both SMI/PVME and SMI/PMMA blends had lower critical solution temperature behavior. The imidization of SMA increased the phase‐separation temperature of the SMA/PVME blend and decreased that of the SMA/PMMA blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Direct polymer reaction of poly(styrene‐co‐maleic anhydride): Polymeric imidization

Using direct polymer reaction of poly(styrene‐co‐maleic anhydride) (SMA), a synthesis of copolymer of styrene and N‐aryl succinimide (SMI) has been investigated. SMI copolymers were synthesized from SMA copolymers by a concerted two‐step reaction, which consisted of the condensation reaction (step 1) of SMA with aromatic amine to prepare a precursor, succinamic acid, for imide formation and the cyclodehydration reaction (step 2) of succinamic acid. In this article, the application of Searle's preparation method of N‐aryl or N‐alkyl maleimide to the direct polymer reaction for SMI was attempted. Compared with synthesis of monomeric imides, the imide formation in polymeric condition appeared to be a little more sensitive to the reaction condition. The optimum condition for maximum conversion was examined in terms of time, temperature, and the amount of reactants. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1187–1196, 1999     

Synthesis and characterization of novel organosoluble biosourced poly(ester imide)s based on 1,4:3,6 -dianhydrohexitols suited for adhesives applications

A new series of poly(ester imide)s were prepared from the polycondensation of isosorbide and a series of synthesized diacyl chloride monomers based on a reaction between 1,2,4-Benzenetricarboxylic anhydride (TMA) and various diamines. The structures of the resulting polymers were confirmed by Fourier transform infrared spectroscopy (FTIR) and ¹³C NMR spectra. Inherent viscosities and size exclusion chromatography (SEC) measurements proved the formation of high molecular weight poly(ester imide)s. The thermogravimetric analysis (TGA) showed deterioration temperature in the range of 221–400 °C indicating a good thermal stability. The differential scanning calorimetry (DSC) measurements revealed high glass transition temperature in the range of 67–185 °C. Wide angle X-ray diffraction measurements showed that the studied poly(ester imide)s were semi-crystalline. Most of the synthesized poly(ester imide) exhibited a good adhesion ability and tensile strength values comparable to analogous polymers.     

苯乙烯-马来酸酐共聚物的酯化改性及其对炭黑的分散性能

采用异丁醇对苯乙烯-马来酸酐共聚物(SMA)进行酯化改性,研究了反应温度、时间、催化剂用量、异丁醇用量等因素对共聚物酸值的影响。红外光谱测试表明,SMA中酸酐与异丁醇发生了酯化反应。在以丁酮为反应溶剂,SMA质量占反应体系总质量的5%,异丁醇质量占反应体系总质量的12%,对甲苯磺酸质量占SMA质量的1%,反应温度80℃,反应时间4 h的条件下,SMA部分酯化物(SME)的酸值降低到了271.6 mg KOH/g。炭黑分散研究结果表明,SME对炭黑分散效率优于SMA,当SME酸值低于355.1 mg KOH/g,其用量为炭黑质量的20%,pH=9时,制备炭黑分散体平均粒径为154 nm,制备的炭黑分散体表现出良好的离心稳定性。     

In situ compatibilization of polystyrene and polyurethane blends by using poly(styrene-co-maleic anhydride) as reactive compatibilizer

Blends of polystyrene (PS) and polyurethane (PU) elastomer were obtained by melt mixing, using poly(styrene-co-maleic anhydride) (SMA) containing 7 wt % of maleic anhydride groups as a reactive compatibilizer. Polyurethanes containing polyester flexible segments, PU-es, and polyether flexible segments, PU-et, were used. These polyurethanes were crosslinked with dicumyl peroxide or sulfur to improve their mechanical properties. The anhydride groups of SMA can react with the PU groups and form an in situ graft copolymer at the interface of the blends during their preparation. The rheological behavior was accompanied by torque versus time curves and an increase in the torque during the melt mixing was observed for all the reactive blends, indicating the occurrence of a reaction. Solubility tests, gel permeation chromatography, and scanning electronic microscopy confirmed the formation of a graft copolymer generated in situ during the melt blending. These results also indicate that this graft copolymer contains C C bond between SMA and PU chains. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2514–2524, 2001     

苯乙烯-马来酸酐共聚物的酯化改性及其对碳黑的分散性能

采用脂肪醇对苯乙烯-马来酸酐共聚物（SMA）进行酯化改性,研究了反应温度、时间、催化剂用量、脂肪醇结构和用量等反应条件对SMA酯化程度的影响。红外光谱测试结果表明SMA酯化改性成功,其较佳的改性工艺条件为异丁醇对SMA的摩尔用量12%,对甲苯磺酸对SMA的质量分数为1%,在80℃条件下反应4h,此时SMA部分酯化物（SME）的酯化度达到了35%。碳黑分散研究结果表明SME对碳黑分散效率明显优于SMA,当SME酯化度超过15%,用量对碳黑质量为20%,pH为9时,制备碳黑分散体粒径为160nm,得到的分散体表现出良好的耐热和离心稳定性。     

High oxidation resistance of hot pressed silicon nitride containing yttria and lanthania

Oxidation tests were carried out on Si₃N₄–La₂O₃–Y₂O₃ hot pressed ceramics up to 1500°C. Morphological and analytical characterizations were performed on surfaces and reaction scales after oxidation and correlated with the oxidation kinetics. (Near)-parabolic behaviour was observed at temperatures <1450°C for short periods, while for higher temperatures and longer exposures the kinetics shifted to a linear behaviour. Moreover the excellent oxidation resistance (as demonstrated by extremely low weight gains), particularly up to 1450°C, was related to the high refractoriness of the grain boundary phases in this additive system. Strength degradation after oxidation at several temperatures was also studied and discussed.     

STUDIES ON FRYING KINETICS AND QUALITY OF FRENCH FRIES

Effects of temperature of oil (160, 170 and 180° C) and duration of pre-drying (0.00, 0.25, 0.50, 0.75 and 1.00 h) on the kinetics of moisture removal and oil uptake, and quality of French fries were studied. Frying times at each combination of temperature and pre-drying duration were standardized on the basis of sensory characteristics of the product in the preliminary trials. Results indicated that the rate of both moisture loss and oil uptake were higher in the beginning followed by a decrease in the later stages of frying. Mathematical models were developed to describe both the moisture removal and oil uptake by French fries. French fries prepared from potato fingers blanched in water for 4 min at 85° C and fried (without pre-drying) at 180° C were judged to be the most acceptable.     

Preparation and characterization of the copolymer containing N‐pyridyl bi(methacryl)imide unit

The copolymer of methacrylic acid anhydride and N‐2‐pyridyl bi(methacryl)imide was prepared based on the reaction of polymethacrylic acid with 2‐pyridylamine. The molecular structure was characterized by ¹H‐NMR, FTIR, UV–Vis, and circular dichroism techniques. The physical properties of polymethacrylic acid change significantly after an introduction of 6 mol % N‐2‐pyridyl bi(methacryl)imide unit. In particular, the thermal degradation of the polymer was systematically studied in flowing nitrogen and air from room temperature to 800°C by thermogravimetry at a constant heating rate of 10°C/min. In both atmospheres, a four‐stage degradation process of the copolymer of methacrylic acid anhydride and N‐2‐pyridyl bi(methacryl)imide was revealed. The initial thermal degradation temperature T_d, and the first, second, and third temperatures at the maximum weight‐loss rate T_dm1, T_dm2, and T_dm3 all decrease with decreasing sample size or changing testing atmosphere from nitrogen to air, but the fourth temperature at the maximum weight‐loss rate T_dm4 increases. The maximum weight‐loss rate, char yield at elevated temperature, four‐stage decomposition process, and three kinetic parameters of the thermal degradation were discussed in detail. It is suggested that the copolymer of methacrylic acid anhydride and N‐2‐pyridyl bi(methacryl)imide exhibits low thermal stability and multistage degradation characteristics. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1673–1678, 2002     

Thermal Decomposition Of Carbonyl Sulfide At Temperatures Encountered In The Front End Of Modified Claus Plants

Understanding the kinetics of the formation and consumption of COS and CS₂ in the front end of the modified Claus process will be a significant step towards reducing the environmental impact of these plants. Specifically, homogeneous intrinsic rate expressions are needed for engineering design and simulation, which will lead to new, optimized ways of operating these plants. Hence, a high-temperature kinetic study of the COS decomposition reaction was carried out. Experiments were performed with inlet COS compositions in the range of 0.20-2.33 mol%, with pressures at 101-150 kPa and temperatures at 800-1100°C; these conditions cover the conditions typically encountered in the front end of the modified Claus process. The experimental results showed that COS conversion is dependent on the inlet concentration of COS, which contrasts with previously reported higher temperature studies. Finally, the COS decomposition kinetics were modeled as the sum of two reactions, which provided a satisfactory representation of experimental data.     

The effect of oxygen and the reduction temperature of the Pt/Al2O3 catalyst in enantioselective hydrogenation of 1-phenyl-1,2-propanedione

The effect of oxygen and catalyst reduction temperature in enantioselective hydrogenation of 1-phenyl-1,2-propanedione over commercial Pt/Al₂O₃ catalyst was investigated. Dichloromethane was used as solvent. The catalyst was modified in situ with (−)-cinchonidine. Relatively high enantiomeric excesses (65%) of (R)-1-hydroxy-1-phenyl-2-propanone were obtained with the solvent used as received, i.e. containing traces of dissolved oxygen and other impurities. Dichloromethane dissociated partially on the Pt/Al₂O₃ surface causing desorption of methane, ethene and HCl from the catalyst during TPD according to mass spectrometric analysis. Under anaerobic conditions the reaction rate was low giving only about 40% enantiomeric excesses of (R)-1-hydroxy-1-phenyl-2-propanone. When injecting 5 mm³ of oxygen into the reactor a beneficial effect was observed (i.e. higher reaction rate and enantiomeric excess) in comparison with anaerobic conditions. Poisoning effect of oxygen was observed when injecting 500 mm³ of oxygen into the reactor. Effect of catalyst reduction temperature was studied at three different temperatures (170, 400 and 455°C). Highest reaction rates and enantiomeric excesses were obtained with the catalyst reduced at 400°C. Methane was desorbed from the catalyst at temperatures between 263 and 383°C which could be the explanation for the lower activity of the catalyst reduced at 170°C. It was demonstrated that small amounts of oxygen can have a beneficial effect in enantioselective hydrogenation of 1-phenyl-1,2-propanedione and also that catalyst reduction temperature plays an important role in obtaining high enantiomeric excesses.