Anhydride Content Research Articles

Transfluthrin: Comparative efficacy and toxicity of reference and generic versions

Stringent requirements are in place for the evaluation and registration of new compounds with biocidal or pesticidal activities. However, the registration requirements for established compounds from new suppliers or for established compounds produced by a different manufacturing process have been less clear and ambiguity exists as to how ‘equivalence of health hazards’ can unequivocally be demonstrated analytically and by toxicological assays. The case presented in this analysis focuses on the chiral pyrethroid transfluthrin (TFL) synthesized by esterification of an acid chloride and alcoholic moiety. According to any modifications of the process of synthesis and purification, new potentially highly toxic and yet chemically reactive impurities in low concentrations (<0.1%) may be formed. Amongst these, that with the structural alert ‘organic acid anhydride’ was given heightened concern as the most potent putative toxicologically significant impurity. The course taken in this analysis focused on the comparison of reference TFL with commercialized generic TFL from two alternative manufacturing sources in India and China. Despite their apparent high racemic purity, TFLs from generic sources were biologically less effective, genotoxic in the Ames’ assay, demonstrated sensory lung irritation and lung/skin sensitization in specialized bioassays. While the off-patent reference TFL was unequivocally negative in all assays (anhydride content not detectable, LOQ <0.01%), positive results with high batch-to-batch variability were a frequent outcome in generic TFLs. Tier I analytical assays failed to detect this relevant impurity in the absence of impurity-specific optimized analytical procedures. This finding suggests that a well-balanced combined approach of analytical and toxicological assays provides the best means to assure that all critical impurities are identified and accounted for. Similarly, putative ‘structural alert’-based toxicity tests proved to be more predictive than any indiscriminant battery of standard bioassays commonly applied to demonstrate equivalence, such as acute oral/dermal toxicity and/or eye/skin irritation assays.

Synthesis, characterization, and properties of acrylate‐modified tung‐oil waterborne insulation varnish

ABSTRACTAn acrylate‐modified tung‐oil waterborne insulation varnish was synthesized from tung oil, maleic anhydride, and acrylates via a Diels–Alder reaction and free‐radical polymerization, and the varnish could be solidified at a relatively low temperature with blocked hexamethylene diisocyanate as a curing agent. The resulting films were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The insulation properties (electrical insulation strength, volume resistivity, and surface resistivity) of the varnish films were tested, and the resistances of films to salted water were evaluated. With an increase in the maleic anhydride content, the thermal stability of the film was improved, whereas the electrical insulation strength, volume resistivity, and surface resistivity decreased. The electrical insulation strength of the film after it was immersed in the NaCl solution was lower than that in dry state, and it decreased as the immersed time was prolonged. In particular, the electrical insulation strength loss of the film increased significantly at maleic anhydride contents beyond 25 wt %. Furthermore, the hardness of the film increased with increasing methyl methacrylate/N‐butyl acrylate ratio, whereas the flexibility and adhesion of film decreased to a certain degree at the same time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41608.

Maleated trans-1,4-polyisoprene from Eucommia ulmoides Oliver with dynamic network structure and its shape memory property

We developed a bio-based shape memory polymer with dynamically crosslinked network structure from trans-1,4-polyisoprene (TPI) derived from Eucommia ulmoides Oliver. Grafting of maleic anhydride onto TPI was performed in 1,2-dichlorobenzene, and the subsequent hydrolysis gave maleated trans-1,4-polyisoprene (MTPI). Increasing trend of the grafted maleic moiety was observed with increasing the concentration of maleic anhydride in the grafting reaction. With increase in maleic content, the glass transition temperature (Tg) of the resulting polymer increased, whereas the crystallinity decreased. The maximum stress of the MTPI with carboxylates was larger than that of the protonated MTPI. Above the melting temperature, the Young's modulus of MTPI with carboxylates was higher than that of neat TPI and the protonated MTPI, due to dynamically crosslinked network structure. Furthermore, the MTPI with 1% carboxylate content exhibited excellent shape memory-recovery properties, exploiting the combination of the physical crosslinking and the melting of the crystal. The resulting materials are expected to contribute to the development of bio-based intelligent materials.

Physico-chemical properties of acetylated starches from Indian black gram (Phaseolus mungo L.) cultivars.

Starches separated from three black gram cultivars were modified by acetylation and compared to their native starches. Acetylation was carried out by treating starches with 0.04 and 0.08g of acetic anhydride/g of starch dry weight basis (db) at 25°C. The extent of acetylation increased proportionally with the concentration of acetic anhydride used. Retrogradation of acetylated starch pastes decreased significantly (p ≤ 0.05) as revealed by significant decrease in syneresis, increased freeze thaw stability and increased light transmittance. The pasting curves of 10.7% starch slurries showed that acetylation decreased the setback viscosity values by 51.2-82.8% and pasting temperature by 3.1-5.6°C than respective native starches. Differential scanning calorimetry observations also revealed significant decrease in gelatinisation temperature of acetylated starches than native starches. Hardness and adhesiveness of starch gels varied between 10.3 and 32.6g and 4.6-82.3gs, respectively which were significantly lower than corresponding native starch gels.

Research into the specifications of woven composites obtained from raffia fibers pretreated using the ecological method

Studies on using cellulosic natural fibers as reinforcement for composites are rapidly growing. The aim of this study is using a raffia-based woven fabric as reinforcement for composites that are grown in the Mediterranean Zone of Turkey. These fabrics benefit from their mechanical performances, low density and their biodegradability. However, it is necessary for the fabrics to form adhesion in the matrix. Therefore, chemical processes should be applied onto the surface of the raffia-based woven fabrics. In this study, three different formulations (different concentrations of maleic anhydride, formic acid and acetic acid) were applied by using conventional and microwave energy on the raffia fabrics. At the end of the application, composite structures were formed by using the fabric as the reinforcement layer and isophtalic polyester as the matrix by the vacuum infusion method.The composite structures were characterized by attenuated total reflectance scanning electron microscope analysis and their mechanical tests were performed through tensile testing.Considering all results, the combination of acetic acid with the microwave process was found to modify the raffia fabric surfaces.

Effect of acetyl esterification on physicochemical properties of chick pea (Cicer arietinum L.) starch.

Acetyl esterification of isolated Bengal gram starch was carried out using acetic anhydride as reactant. Modification of native starch at variant concentrations of acetic anhydride (6, 8 and 10%, w/w) resulted in modified starch with 2.14, 3.35, 4.47% acetyl content and 0.082, 0.130 and 0.176° of substitution (DS) respectively. The acetyl esterification of native starch brought significant changes in physicochemical properties with respect to pasting behavior, granule morphology, thermal properties and retrogradation profile. Acetyl modifications of native starch increased swelling capacity, water absorption power and oil absorption capability by 17, 13 and 20% respectively. Acetylation has decreased pasting temperature, pasting time, final viscosity and set back viscosity due to increase in amylsoe content, hydrogen bonding and porosity of starch granule. The acetyl modification was confirmed by IR spectra with the presence of an ester carbonyl group (C = O) at 1720.3cm(-1) and absorption band at 174.8cm(-1). In DSC evaluation there was decrease in To, Tp, Tc and ΔH of acetylated starch than native starch which resulted in reduced retrogradation by 56%.

Changes in Cell Wall Dimensions during the Different Stages of Furfuryl Alcohol Modification

Furfuryl alcohol modification of wood is a well-known process for wood property enhancement. The present project focuses on veneer molding for high-value applications using the plasticizing effect of furfuryl alcohol. Adding maleic anhydride to furfuryl alcohol leads to an acid-catalyzed polymerization of furfuryl alcohol at elevated temperatures, fixing the shape of the veneer. In contrast to water or water vapor treatment, furfuryl alcohol-modified cell walls face a lower degree of shrinkage due to the polymer formation and possibly experience less drying-induced cracks. Earlier studies show a distinct influence of maleic anhydride on the curing of furfuryl alcohol. To determine the impact of different maleic anhydride contents on the polymer formation and the corresponding shrinkage of wood cell walls, microscopic studies were carried out on various maple microtome sections (Acer sp.), i.e., when dry, water-impregnated, after furfuryl alcohol impregnation, and after curing at elevated temperatures. At each state, the cell walls of 30 appointed early wood cells were determined by cell wall area measurements. The lowest shrinkage of impregnated samples was realized by using 10 wt% maleic anhydride in the impregnation solution and after 48 h soaking. Here, cell wall shrinkage could be reduced by approx. 42.6% compared to water-impregnation.

랜덤 PP의 반응압출 및 PP/Pulp 복합체 특성에 대한 스티렌과 무수말레인산 함량의 영향

랜덤 폴리프로필렌(random polypropylene, rPP)의 무수말레인산(maleic anhydride, MAH) 반응압출에 대한 MAH 함량 및 스티렌/MAH 몰비의 영향을 고찰하기 위해 이축압출기(twin screw extruder)를 이용하여 MAH가 그라프트된 rPP(MAH-g-rPP)를 제조하였다. MAH의 함량은 0.5, 1.0, 3.0, 5.0 phr이었고, 스티렌/MAH 몰비는 0, 1, 2로 하였으며, 개시제로는 dicumyl peroxide (DCP)가 사용되었다. MAH의 그라프트 정도는 FT-IR을 이용하여 <TEX>$1700cm^{-1}$</TEX> 근처에서 나타나는 카르보닐기(C = O) 신축진동 피크의 존재 여부를 통해 확인하였으며, <TEX>$3000cm^{-1}$</TEX> 근처의 C-H 신축진동을 기준으로 하여 정량한 결과 그라프트 반응이 MAH 함량이 3.0 phr까지 증가하는 경향을 보여주었고, 스티렌 몰비는 1.0일 때 최적을 나타내었다. MAH-g-rPP와 MAH-g-rPP가 5.0 phr 포함된 PP/MAH-g-rPP/pulp 복합체의 열적특성, 결정화 특성 등을 시차주사열용량분석기(DSC), 열중량분석기(TGA), X-선 회절분석(XRD), 편광현미경(POM) 등을 이용하여 관찰하였다. 비등온 결정화온도는 rPP-g-MAH가 첨가되었을 때 감소하는 경향을 나타내었고, PP/MAH-g-rPP/pulp 복합체의 인장특성과 인장시험 후 파단면의 SEM을 측정한 결과, MAH 함량 1.0 wt%, 스티렌/MAH 몰비 1.0일 때 상용화제로의 역할이 가장 우수한 것으로 나타났다. 복합체의 가공성 비교를 위해 복소 점도와 전단박하(shear thinning) 정도를 동적유변측정기를 이용하여 측정하였다. 상용화제를 가지는 복합체의 경우 낮은 멱수 법칙 지수(n)를 보여주었다. In order to analyze the effect of maleic anhydride (MAH) content and styrene monomer (SM)/MAH mole ratio on reactive extrusion of maleic anhydride grafted random polypropylenes (MAH-g-rPP), MAH-g-rPPs were prepared by using a twin screw extruder. MAH contents were 0.5, 1.0, 3.0, and 5.0 phr and SM/initiator mole ratio was 0.0, 1.0, and 2.0. Dicumyl peroxide (DCP) was used as an initiator. The graft degree of MAH was confirmed by the existence of carbonyl group (C = O) stretching peak at <TEX>$1700cm^{-1}$</TEX> from FT-IR spectrum. The degree of graft reaction increased up to 3.0 phr MAH and showed the optimum value at 1.0 SM/MAH mole ratio from the area ratio of C = O and C-H stretching peak. Thermal and crystallization properties of MAH-g-rPP and PP/MAH-g-rPP/pulp composites were investigated by DSC, TGA, XRD, and POM. There was a decrease in non-isothermal crystallization temperature of PP/MAH-g-PP/pulp composites. Based on tensile properties and SEM pictures for the fractured surface of PP/MAH-g-PP/pulp composites, MAH content of 1.0 wt% and SM/MAH mole ratio of 1.0 were the optimum formulation as the compatibilizer. The rheological properties of the composites were measured by dynamic Rheometer to compare the processability of the composites with and without compatibilizer. The power law index showed slightly low value at the composites with compatibilizer.

Influence of MA‐g‐HDPE compatibilizer content on quality and adhesion/bending strength of polyethylene/O‐MMT coating films

ABSTRACTHigh density polyethylene/organo‐modified montmorillonite composites whit various concentrations of maleic anhydride grafted high density polyethylene (MA‐g‐HDPE) as compatibilizer (5–20 wt %) have been prepared by melt process. The extruded composite powders are applied on the treated steel surfaces using spray electrostatic powder technique, followed by oven curing at various temperatures (180°C–220°C) and times (15–45 min). The surface uniformity of produced coating films is studied by scanning electron microscopy. Comparison of micrographs of the coatings shows the composite coating films are measured using standard methods. The uniformity, adhesion, and bending strength of the coating films are compared to select high performance coatings. The results indicate that the presence of 15 wt % MA‐g‐HDPE in the coatings shows the highest properties (adhesion and bending strength) and more surface uniformity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40926.

Gelatin-based biomaterial engineering with anhydride-containing oligomeric cross-linkers.

Chemically cross-linked gelatin hydrogels are versatile cell-adhesive hydrogel materials that have been established for a variety of biomedical applications. The most prominent cross-linker is glutaraldehyde, which, however, has been described to cause compatibility problems and loss of microscopic but relevant structural features. A recently developed oligomeric cross-linker that contains anhydride functionalities was evaluated as cross-linker for the fabrication of gelatin-based hydrogels and microparticles. In a fast curing reaction, hydrogels composed of gelatin and oligomeric cross-linker were fabricated with good conversion over a wide concentration range of constituents and with cross-linkers of different anhydride contents. Hydrogel properties, such as dry weight and mechanics, could be controlled by hydrogel composition and rheological properties correlated to elastic moduli from 1 to 10 kPa. The gels were shown to be cytocompatible and promoted cell adhesion. In soft formulations, cells migrated into the hydrogel bulk. Gelatin microparticles prepared by a standard water-in-oil emulsion technique were also treated with the novel oligomers, and cross-linking degrees matching those obtained with glutaraldehyde were obtained. At the same time, fewer interparticular cross-links were observed. Fluorescein-derivatized cross-linkers yielded labeled microparticles in a concentration-dependent manner. The oligomeric cross-linkers are presented as an efficient and possibly more functional and compatible alternative to glutaraldehyde. The engineered hydrogel materials hold potential for various biomedical applications.

Physicochemical and release characteristics of acetylated Indian palmyrah retrograded shoot starch

The aim of the present study is to determine the influence of serial modifications, including retrogradation followed by acetylation on morphological, physicochemical and drug release properties of retrograded Indian palmyrah (Borassus flabellifer L.) shoot starch. The acetylated retrograded starches prepared by using different concentrations of acetic anhydride were shown a degree of substitution (DS) in the range of 0.16–0.55. Acetylation of retrograded starch produced significant morphological changes from rough to smooth surface. The amylose content, water holding capacity, swelling and solubility power tend to increase with increase in DS. A strong peak at 1751 and 1032cm−1 confirms the formation of acetylated retrograded starch. The TGA data reveal that with increase in DS there is an increased thermal stability and decreased bound water of starch. The elemental analysis also confirms the addition of acetyl groups because of increased carbon and hydrogen content. The matrix tablets of acetylated retrograded starch with high DS showed a delayed release in gastric pH and sustained release in simulated intestinal fluid. Overall, this result suggested that acetylated retrograded starch with high DS are thermally stable and can be used for formulating protein and peptide drugs for colon targeting.

Physical properties of maleated poly(lactic acid) composites containing different functionalized multiwalled carbon nanotubes.

In the current study, maleic anhydride-grafted poly(lactic acid) (MA-g-PLA) was prepared by using a reactive blending method to improve interfacial interaction and compatibilization in PLA/functionalized multiwalled carbon nanotube nanocomposites. Concentrations of maleic anhydride and initiator were varied at 3, 5 wt% and 0-0.7 wt%, respectively. The maleation content was determined by using a titration method, in which MA-g-PLA containing the optimum degree of grafting was subsequently chosen to prepare the nanocomposites containing hydroxyl and carboxylic functionalized multiwalled carbon nanotubes at various contents (0-5 wt%) and compared with the ones prepared with non-functionalized type. Dispersion morphology, thermal and mechanical properties of the resultant nanocomposites were investigated by means of transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and tensile measurement. It was shown that the compatibility between the nanotubes and MA-g-PLA was improved where the functionalized nanotubes exhibited a better dispersion and mechanical property than the nonfunctionalized nanotubes. With increasing concentration of carbon nanotubes, tensile strength and Young's modulus of the nanocomposites were correspondingly enhanced, in which at 5 wt% addition yielded the highest values at 90 MPa and 10 GPa, respectively.

Green Synthesis and Physical Properties of poly(Vinyl Alcohol) Maleated in an Aqueous Solutions

The objective of this work was to synthesize maleated poly(vinyl alcohol) (PVAM) in aqueous solution through esterification, and to seek near optimal degree of grafting and crosslinking. The effects of maleic anhydride (MA) content on the properties of PVAM were investigated. The experimental observations included characterizations by ATR–FTIR and thermo gravimetric analyses (TGA), and determinations of grafting ratio, dynamic viscosity, and swelling ratio. The percentage degree of grafting, dynamic viscosity, and particle size increased with MA content, while the swelling ratio decreased due to copolymerization of poly(vinyl alcohol) (PVA) and MA. The peaks at 945 and 918 cm−1 in the spectrum of PVA indicated the presence of carboxylic groups, while in the spectrum of PVAM only one peak at 920 cm−1 indicated presence of carboxylic groups, due to copolymerization of PVA and MA. Moreover, the thermal stability of PVA-g-MA was enhanced as observed from TGA. The results suggest 7:3 PVA/MA mass ratio as near optimal for PVA-g-MA.

Interfacial adhesion of glass fibre reinforced polypropylene–maleic anhydride modified polypropylene copolymer composites

In this work, the interfacial adhesion between the glass fibre and polypropylene–maleic anhydride modified polypropylene copolymer has been studied using a microbond test. The interfacial shear strength of the composite increased from 6.58 to 14.85 MPa, with the increase of the content of maleic anhydride modified polypropylene from 0 to 5% in the matrix composition. Oxygen plasma and γ-aminopropyltrimethoxysilane surface treatments were also introduced to modify the surface chemistry of the glass fibre. Compared with γ-aminopropyltrimethoxysilane surface treatment and the control, the interfacial adhesion of the composites of oxygen plasma was stronger in the same content of maleic anhydride modified polypropylene. This trend matches the law of surface morphology, which was imaged by scanning electron microscope. And there was no transcrystallisation at the interface of fibre and matrix resin, and no crystalline morphology change on the matrix resin by a polarised optical microscope.

Thermal and Tensile Mechanical Behavior of Acetic Anhydride Treated Silk Fibres

Acylation of fibres can provide a route to have materials with better water proofing capability. In our present study, silk fibres were treated with various concentration (5, 10 and15 wt.%) of acetic anhydride aqueous solution and then thermal properties, tensile mechanical behaviour and moisture content of acetic anhydride treated silk fibres were studied. Raw silk fibres were taken as control for comparison. It was found that elastic modulus and tensile strength of silk fibres were increased with increasing acetic anhydride concentration while elongation at break was decreased with increase of acetic anhydride content in solution. Silk fibres treated with 15 wt. % of acetic anhydride solution exhibited about 141% (from 17 GPa to 41 GPa) improvement in elastic modulus. It was also found that acetic anhydride treated silk fibres displayed higher thermal resistance and lower moisture content as compared to untreated silk fibres.

Value Adding of Skim Natural Rubber by Grafting with Maleic Anhydride

This research investigates the potential for grafting skim natural rubber with maleic anhydride to produce maleated rubber with the aim to increase value of skim natural rubber. In this study, grafting of skim natural rubber was compared to those of natural rubber block. Moreover, the effect of protein in skim rubber was also investigated by comparing with grafting of deprotinized skim rubber. Here, the grafting reactions were carried out by reactive melt-mixing method. The effect of maleic anhydride concentration and type of raw materials were investigated. Quantities of the grafted anhydride (MA) and the amount of double bonds were determined by using FTIR analysis.We found that nitrogen content of raw material could potentially affected the grafting level, especially at low MA content, and that the grafting reaction occurred in parallel with crosslinking reaction(gel). The potential model of reaction mechanism was analyzed from FTIR spectra and the gel content.

Thermal and mechanical properties of polysulfide/epoxy copolymer system: the effect of anhydride content

Polymerization of a ternary system containing polysulfide (PS), as a liquid elastomer, diglycidylether of bisphenol A resin, and phthalic anhydride was conducted using “design of experiment” technique. The polymerization progress with respect to concentration variations of components were studied by Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy studies showed that the anhydride plays a decisive role in curing reaction so that, in its absence, the epoxy/PS mixture becomes gel in about 2 hr, whereas, by addition of the anhydride, the pot life of the system can be extended to 48 hr. The cured samples were investigated by thermal gravimetry analysis and differential scanning calorimetry to evaluate thermal properties. Thermal gravimetry analysis and differential scanning calorimetry results indicated that two different soft and hard segments are formed, which have different thermal decompositions. The soft segment consists of loose etheric bonds, which are attributed to PS, and the hard segment is formed during the etherification and esterification reactions of the epoxy resin. Tensile strength test was performed to investigate the mechanical properties of PS/epoxy/anhydride-cured systems. The results showed that the tensile strength, elongation-at-break, and the fracture energy of specimens are essentially dependent on PS/anhydride ratios. Two different segments impart high strength and ductility simultaneously. Copyright © 2013 John Wiley & Sons, Ltd.

Reactive functionalization of poly(lactic acid), PLA: Effects of the reactive modifier, initiator and processing conditions on the final grafted maleic anhydride content and molecular weight of PLA

Abstract A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis( tert -butylperoxy)-2,5-dimethyl hexane (Luperox or L101) content, and TSE screw speed on the degree of grafted MA (MA g ) and number average molecular weight ( M n ) of maleated PLA (PLA- g -MA), which can be used as a reactive compatibilizer in production of PLA blends with various components. PLA- g -MA's FTIR peaks indicated that MA was grafted onto the PLA backbone and oligomeric MA was also present. A maximum of 0.52 wt% MA g determined by titration was achieved at the expense of a 50% reduction of M n and an increase in the polydispersity index to around 2.0. Generally, increasing L101 increased the degree of grafting and decreased M n . L101 and MA g had a large effect on the stability of PLA- g -MA's M n during storage. Nominally, amounts of MA equal to 4.5 wt%, L101 between 0.45 and 0.65 wt%, and screw speed of 20 rpm provided the optimal conditions for grafting MA onto PLA.

Physico-chemical properties investigation of softwood surface after treatment with organic anhydride

Abstract Wood originating from a softwood species was subjected to chemical treatment by reaction with succinic anhydride in N, N-dimethylformamide at different concentration values. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis were used to study changes that occurred on a softwood surface. The extent of chemical treatment on softwood was evaluated by determining the weight percent gain values. Thermal properties of modified softwood and the water absorption were also evaluated. The chemical treatment with succinic anhydride influenced the thermal stability of the softwood samples with increasing anhydride concentration levels.

Pectinic substances from leaves of Ungernia victoris

A low-esterified pectin with MW 51,300 Da, [α] D +125°, and galacturonic anhydride content 68.3% was isolated in 6.8% yield from leaves of Ungernia victoris. Partial acid hydrolysis of the pectinic substances produced galacturonan with [α] D +175° and MW 34,500 Da. The structure of the galacturonan was studied by 13 C NMR spectroscopy.