Maleic Anhydride Units Research Articles

Estimation of interaction energies by the critical molecular weight method: 2. Blends with polysulfones

AbstractThe interaction energies between PS, Pα‐MS, and PMMA, as well as acrylonitrile and maleic anhydride units, with a series of polysulfones were quantitatively determined from oligomer/oligomer, oligomer/homopolymer, and homopolymer/copolymer blends. Interaction energies were calculated from the Flory‐Huggins theory and the Sanchez‐Lacombe equation of state theory using experimental cloud points or miscibility boundaries. Alkyl addition to the phenyl rings of polysulfone is favorable for miscibility with polystyrene whereas halogenation of the bisphenol connector unit favors miscibility with poly(methyl methacrylate). Interaction energies are quantitatively ranked and described qualitatively in terms of changes in the electronic charge distribution of the polymer repeat units as calculated by SYBYL software. © 1994 John Wiley & Sons, Inc.

Ellipsometric analysis on the in situ reactive compatibilization of immiscible polymer blends

Time-resolved ellipsometric analysis was carried out to investigate the change in interfacial thickness between amorphous nylon and styrenic polymers during annealing at high temperatures (170–210°C). The styrenic polymers were neat poly(styrene- co-maleic anhydride) (SMA) and single-phase mixtures of SMA with poly(styrene- co-acrylonitrile) (SAN). Here SMA is known to be reactive with the chain end of nylon, forming a graft copolymer at the interface between the phases. The interfacial thickness increased with annealing time and then attained a constant value, depending on temperature and net concentration of reactive sites (maleic anhydride units) in the styrenic phase. The interface established at late stages was tremendously thick, ranging from 10 to 50 nm. The thickest interface is several times the coil size of the component polymer. This may suggest drawing of the whole graft copolymer chain into the interface to establish a smooth concentration gradient at the interface. Formation of such a thick interface seems to be characteristic of a reactive system in which chemical reaction induces deviation from an equilibrium interface in a ternary system consisting of polymer A, polymer B and A–B graft or block copolymer. Thus the study provided a preliminary understanding of the in situ reactive compatibilization of polymer blends in terms of the interfacial problem.

Solvent effects on the microstructure of styrene/maleic anhydride copolymers

The configuration of maleic anhydride (MA) units in copolymers of styrene with MA prepared in methyl ethyl ketone and in CHCl 3 at 50°C over a range of comonomer feed mole fractions were determined by 13 C NMR spectroscopy, along with the comonomer unit sequence distributions of each copolymer. The results were then analyzed in terms of the extent of 1:1 electron donor-acceptor (EDA) complex formation in each solvent and the role of the EDA complex in alternating copolymerization

Ignition of maleic anhydride soaked insulation

Abstract As part of an investigation into a fire which occurred on a maleic anhydride (MAN) unit, the ignition properties of maleic anhydride in insulation were examined. It was determined that insulation soaked with this material can ignite at temperatures will below the auto-ignition temperature and less than the temperature of steam commonly used in heat tracing. This suggests that the danger of insulation fires is not limited to organic heat transfer fluids or high molecular weight hydrocarbons. These fluids have been the focus of much of the previous work in this area.

Determination of the stereochemistry of maleic anhydride units in copolymers ofp-chlorostyrene with maleic anhydride via13C NMR spectroscopy

The configuration of maleic anhydride units in p-chlorostyrene/maleic anhydride copolymers prepared in methyl ethyl ketone at 50 ± 0.1°C and the corresponding comonomer unit sequence distributions were determined using the13C DEPT NMR sequence. It was found that the ratio ofcis (erythro) totrans (threo) configurations of maleic anhydride units increased with the degree of alternation of the comonomer units, reaching a constant value of approximately 0.73 when the comonomer units were almost completely alternating.

Maleation of linear low‐density polyethylene by reactive processing

AbstractThe reaction of maleic anhydride (MAH) with molten 2 MI poly(ethylene‐co‐butene‐1) (LLDPE) at 160°C in the presence of peroxyesters (t1/2 < 10 s) as catalysts resulted in the formation of a mixture of cross‐linked and trichlorobenzene‐soluble LLDPE‐g‐MAH. The soluble fraction constituted more than 50% of the mixture and had an MI of 0.0 and an MAH content ranging from 0.3 to 1.8 wt %. The presence of tri(nonylphenyl) phosphite (TNPP) in the LLDPE–MAH–t‐butyl peroctoate (tBPO) reaction at 160°C increased the MI of the soluble product to 0.7–2. The amount of soluble polymer increased at higher TNPP concentrations while its MAH content ranged from 0.05 to 0.54 wt %, with most contents in the 0.2–0.3 wt % range. The color development that usually occurs in polyolefin–MAH reactions was reduced by the presence of TNPP. However, the reaction of TNPP with the peroxide and from the thermal decomposition thereof reduced the availability of the excited species necessary for the appendage of MAH units onto the polyofin.

Quantitative determination of the content of cis/trans configurations of maleic anhydride units in p-methoxystyrene-maleic anhydride copolymers by 13C NMR DEPT experiments

The configuration of maleic anhydride units in p-methoxystyrene-maleic anhydride copolymers prepared in methyl ethyl ketone at 50°C was studied using 13C NMR DEPT experiments. The ratio of cis (erythro) to trans (threo) configurations was found to increase with the tendency of the monomer units to alternate, remaining almost constant at approximately 1.33 when the mole fraction of maleic anhydride in the feed was larger than 0.30 and the monomer unit sequence was almost completely alternating. Also, para substitution on the styrene monomer units was found to greatly improve the resolution of the 13C NMR DEPT spectra for copolymers of p-methoxystyrene and p-chlorostyrene with maleic anhydride as compared with that of styrene-maleic anhydride copolymers.

Copolymers of maleic anhydride with monooctyl itaconate. Synthesis, characterization and viscometric behaviour

Maleic anhydride-monooctyl itaconate copolymer was synthesized by radical polymerization. The viscometric behaviour was studied in dilute solution. The copolymer was fractioned and characterized by size exclusion chromatography membrane osmometry and viscometry. The classical viscometric relationships were established in several solvents. The conformational and thermodynamic parameters K θ and B were evaluated from viscosity data in good solvents using the Stockmayer Fixman, Berry and Kamide-Moore extrapolations. The rigidity parameters σ and C ∞ show flexibility of the polymer chain, due to the incorporation of the maleic anhydride units when the copolymer is compared with the corresponding homopolymer poly(mono-n-octyl itaconate).

Synthesis and microstructure of organotin polymers

IR spectroscopy and derivatography have been used to analyze the intramolecular conversions of the bis-tri- n-butylstanny esters of maleic and fumaric acids and also their copolymers. Thermal isomerization of the maleates to fumarates does not occur up to temperatures of the onset of decomposition of the substances. On free-radical copolymerization of the maleates with styrene there is partial isomerezation and in the structure of the chain, units of the diesters of maleic (85–90%) and fumaric (10–15) acids are found. In the alternating styrene-maleic anhydride copolymers after esterification by organotin oxides the number of isotactic diads may be 10%. Change in the microtacticity is explained by the formation of polycarbanions. Heating of the copolymers to 500 K leads to exothermal change in the configuration of the maleate units and then to their cyclization with the formation of maleic anhydride units.

Silyl enol ethers as monomer. I. Radical copolymerizability of α‐trimethylsilyloxystyrene

Abstractα‐Trimethylsilyloxystyrene (TMSST), the silyl enol ether of acetophenone, was not homopolymerized either by a radical or a cationic initiator. Radical copolymerization of TMSST with styrene (ST) and acrylonitrile (AN) in bulk and the terpolymerization of TMSST, ST, and maleic anhydride (MA) in dioxane were studied at 60°C and the polymerization parameters of TMSST were estimated. The rate of copolymerization decreased with increased amounts of TMSST for both systems. Monomer reactivity ratios were found as follows: r1 = 1.48 and r2 = 0 for the ST (M1)–TMSST (M2) system and r1 = 0.050 and r2 = 0 for the AN (M1)–TMSST (M2) system. The terpolymerization of ST (M1), TMSST (M2), and MA (M3) gave a terpolymer containing ca. 50 mol % of MA units with a varying ratio of TMSST to ST units and the ratio of rate constants of propagation, k32/k31, was found to be 0.39. Q and e values of TMSST were determined using the values shown above to be 0.88 and −1.13, respectively. Attempted desilylation by an acid catalyst for the copolymer of TMSST with ST afforded polystyrene partially substituted with hydroxyl groups at the α‐position.

Thermal degradation aspects of model copolymers based on styrene, maleic anhydride, diethyl maleate and diethyl fumarate

Three copolymers, poly(styrene-maleic anhydride), poly(styrene-diethyl fumarate) and poly(styrene-diethyl maleate) were pyrolysed isothermally at 450 °C for 30 min in a nitrogen atmosphere. The pyrolysis products were separated and identified with a gas chromatograph coupled to a mass spectrometer. In the case of poly(styrene-maleic anhydride) and poly(styrene-diethyl fumarate) toluene, ethylbenzene and styrene were detected as the major pyrolysis products from the styrene moiety. In the case of poly(styrene-diethyl maleate), dimers and trimers of styrene were detected among the pyrolysis products. These results agree well with the conclusions from the IR studies and the reported copolymerisation parameters of the monomers. On-line pyrolysis experiments of poly(styrene-maleic anhydride) showed that the incorporated maleic anhydride units degrade at a temperature around 80 °C lower than the polymer backbone.

Peroxide‐catalyzed grafting of maleic anhydride onto molten polyethylene in the presence of polar organic compounds

AbstractThe crosslinking of LDPE resulting from reaction with dicumyl peroxide at 180°C is increased in the presence of maleic anhydride (MAH). The presence of electron‐donating nitrogen‐containing compounds (amides, lactams, disubstituted aromatic amines, and amine oxides), phosphorous‐containing compounds (phosphites, phosphates, phosphonates, phosphoramides, and phosphine oxides) and sulfur‐containing compounds (sulfoxides, aryl disulfides, and thiazyl disulfides) which inhibit the homopolymerization of MAH but not that of methyl methacrylate, prevents crosslinking and yields soluble PE containing MAH units. Crosslinking, due to coupling of PE˙ macroradicals formed by hydrogen abstraction from PE by excited MAH, is prevented by electron donation from the additive to the MAH+ cation which is present in the MAH+−MAH excimer as well as in the excimer which is appended to the PE.

Radical copolymerisation of maleic anhydride with trans‐stilbene

AbstractRadical copolymerisations of maleic anhydride and trarcs‐stilbene have been carried out in methyl ethyl ketone at 60°C using 2,2′‐azo‐bis‐isobutyronitrile as initiator. The copolymers formed at all feeds are slightly rich in maleic anhydride units but are heterogeneous with regard to both composition and molecular weight distribution. It is concluded that this effect is probably produced by phase separation during the copolymerisation and that any interpretation of copolymerisation rates or copolymer compositions in terms of mechanism is not straightforward.

An ESR Study of the UV Photolysis of Styrene and Maleic Anhydride at 90 K

Abstract Free radicals produced in styrene and maleic anhydride mixtures and in solutions in acetone and chloroform by UV photolysis at 90 K have been studied by electron spin resonance and changes observed on warming. A doublet spectrum observed in all systems containing maleic anhydride has been assigned to the radical formed by H addition to a carbonyl group in the monomer, and not to the corresponding radical on maleic anhydride units in the copolymer or to the maleic anhydride propagating radical. Interpretations of copolymerization mechanisms based on radicals produced in frozen comonomers in bulk or in solution by photolysis or radiolysis must therefore be viewed with caution.

A DSC and DMA study of polymers with crystallizable side chains: Poly (α-olefin-co-maleic anhydride)

Abstract The thermal behavior of a series of poly(α-olefin-co-maleic anhydride) copolymers was studied by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Polymers with side-chain lengths of 16, 18, and 23 carbons were found to have crystallizable side chains. The melting point and heat of fusion of the side chains increased with increasing side-chain length. Glass transition temperatures were observed to be greater than the side-chain melting points. The molecular weight dependence of the Tg's obeyed the Fox-Flory relationship, with Tg ∞ = 129°C and k = 1.5 × 105. A spectroscopic method to monitor the extent of hydrolysis of the maleic anhydride units was developed, and the hydrodynamic volume in THF was observed to be dependent on the extent of hydrolysis.

Synthesis and properties of hydrolyzed polymers of maleic anhydride

Results are presented of investigations into hydrolysis of copolymers of maleic anhydride with styrene, n-butylmethacrylate and ternary copolymers. p K a1 and p K a2 values were determined for hydrolyzed copolymers. On the basis of p K a values in a number of systems and based on results of derivatographic investigations of a hydrolyzed terpolymer a conclusion was drawn about the preferred position of maleic anhydride units in the terpolymer between styrene and n-butylmethacrylate units.

Radical Cyclocopolymerization of Divinyl Ether Derivatives with Maleic Anhydride. The Structure Determination of the Alternating Copolymers by 13C-NMR Spectroscopy

Radical copolymerizations of cis-propenyl vinyl ether, 2-methylpropenyl vinyl ether and cis-dipropenyl ether with maleic anhydride were carried out, and completely cyclized, and alternating copolymers were obtained with the 1: 2 composition of divinyl ethers and maleic anhydride. 13C-NMR spectroscopic data indicated that the polymers contained in common the bicyclic unit composed of one molecule of each monomer and the maleic anhydride unit. The bicyclic unit was characterized by the cis junction and the trans ring closure, and the maleic anhydride unit was formed by trans opening of the double bond. Introduction of methyl substituents do not appear to affect the polymer structure, though assignments become less definite.

Thermal-, photothermal- and photodegradation of copolymers of methyl methacrylate and maleic anhydride

Rates of volatilisation and chain scission have been measured in the thermal degradation, photodegradation in solution, photodegradation in thin films and photothermal degradation of poly(methyl methacrylate) and a series of copolymers of methyl methacrylate with maleic anhydride. In each case the rate of volatilisation is depressed by the maleic anhydride units. On the other hand, rates of chain scission are accelerated by maleic anhydride except in the case of photothermal degradation. These results are discussed from a mechanistic point of view.

NMR investigations on copolymers of maleic anhydride with ethylene

AbstractThe microstructure of copolymers of maleic anhydride with ethylene which were synthesized in two processes differing significantly from one another was studied by means of 1H‐ and 13C‐NMR. The precipitation polymerizates as well as the products synthesized under high pressure have the same basic structure. The maleic anhydride units are found to alternate with ethylene units in the macromolecules. The observed differennces in the microstructure are results of supplementary modification reactions which may take place spontaneously in the precipitation process by alcohols or during storage by atomospheric humidity with the splitting‐up of the anhydride ring. 1H‐ and 13C‐NMR spectroscopy proved as efficient methods for studying these modification processes. The 13C‐NMR spectra allow the conclusion that the microstructure of maleic anhydride copolymers consist of different stereo conformations which occur with different probability.

Vapor‐phase graft copolymerization of binary solid monomers onto poly(ethylene‐co‐vinyl acetate) film by ultraviolet irradiation

AbstractVapor‐phase graft copolymerizations of acenaphthylene–maleimide or acenaphthylene–maleic anhydride binary solid monomers onto poly(ethylene‐co‐vinyl acetate) films were carried out under ultraviolet irradiation. The extent of sorption of single or binary monomers increased with the increasing vinyl acetate content in the backbone polymers. The sorbed binary monomers were mainly composed of acenaphthylene, but the maleimide or maleic anhydride fraction increased with the increasing vinyl acetate content of the films and the composition was little affected by surface hydrolysis. In all series of graft polymerization of single or binary monomers the overall extent of grafting increased with the vinyl acetate content and was suppressed by the surface hydrolysis of the backbone film. The composition of the grafted copolymer, however, differed markedly, depending on the combination of binary monomers. The grafted copolymer in the acenaphthylene–maleimide system was composed mainly of acenaphthylene units, whereas that in the acenaphthylene–maleic anhydride system was composed mainly of maleic anhydride units. The results were compared with those of γ‐ray grafting, and it was suggested that the contribution of a direct supply of monomers from vapor phase and the existence of an acetoxy group on the surface of the film should play an important role in the grafting reaction.