Styrene-methacrylic anhydride composition

Several theoretical treatments of cyclocopolymerization have been reported previously (8-11). These relate the compositions of cyclocopolymers to monomer feed concentrations and appropriate rate constant ratios. To our knowledge, procedures for calculating sequence distributions for either cyclocopolymers or for copolymers derived from them have not been developed previously. In this paper we show that procedures for calculating sequence distributions of terpolymers can be used for this purpose. Most previous studies on styrene-methacrylic anhydride copolymerizations (10,12,13) have shown that a high proportion of the methacrylic anhydride units are cyclized in these polymers. Cyclization constants were determined from monomer feed concentrations and the content of uncyclized methacrylic anhydride units in the copolymers. These studies invoked simplifying assumptions that enabled the conventional copolymer equation to be used in determinations of monomer reactivity ratios for this copolymerization system. 

H-NMR studies. Varian A-60 and HR-100 NMR spectrometers were used to measure the 1H-NMR spectra of styrene-methacrylic anhydride copolymers in DMSO-dg solution at 90° and of the derived styrene-methyl methacrylate copolymers in CCli, and C6D6 solution at 75-80°C. Solvent resonances interfered with composition determinations in the case of styrene-methacrylic anhydride copolymers, but the ratio of uncyclized methacrylic anhydride to styrene units (X) could be measured from the relative intensities of resonances observed at 6=5.72 and 6.15 ppm (olefinic protons) and at 6.5-7.5 ppm (aromatic protons). The compositions of the derived styrene/-MMA copolymers were calculated from the proportion of aromatic proton resonance observed in the spectra of copolymers dissolved in CClm as was described previously (6). Letting Y represent the ratio of styrene to MMA units in the derived copolymers, the compositions of the parent styrene-methacrylic anhydride copolymers were calculated as follows ... 

Table I lists compositions determined this way for styrene-methacrylic anhydride copolymers prepared at 40°.

Compositions of Styrene-Methacrylic Anhydride Copolymers Prepared at 40°... 

B - 6 2.7-3.2 ppm and C - 6 = 2.2-2.7 ppm). Figure 2 compares the aliphatic proton resonance patterns of styrene-MMA copolymers prepared by direct polymerization and by modification of styrene-methacrylic anhydride copolymers. The methoxy and a-methyl proton resonance patterns of the copolymers differ considerably even though they have similar compositions. The proportions of MeO resonance occurring in the A- and B- areas (FAi Fg) were calculated by dividing the A- and B- resonance areas by the total MeO resonance area expected, based on the compositons of the copolymers (i.e., MeO resonance area expected = 3/8 x % MMA/100). The proportion of MeO resonance occurring in the C- area was calculated by subtracting these quantities from one (Fq = 1 - Fa - Fg). 

Following methods reviewed previously (16), these transition probabilities can be used to calculate the compositions of styrene-methacrylic anhydride copolymers. Thus, the method of Price (17) yields the following results, where P(S), P(A) and P(B) represent the relative concentrations of the following groups. 

Of special interest to the present study is the calculation of the compositions and sequence distributions of styrene-MMA copolymers derived from styrene-methacrylic anhydride copolymers. 

In many samples, no resonances due to uncyclized anhydride units were detected. This was particularly true of copolymers with high styrene contents. Table I lists the compositions determined for styrene-methacrylic anhydride copolymers prepared at 40°. The styrene contents of the copolymers are in good agreement with those reported by Smets, et al., for copolymers prepared from comparable monomer ratios, but where the anhydride concentration was 2M. However, Smets, et al. report that 30-50 percent of the anhydride units were uncyclized in their copolymers and it appears that the extent of cyclization is better than 90 percent, generally about... 

Smets, et al. (12) noted that the compositions of styrene-methacrylic anhydride copolymers prepared from given styrene-methacrylic anhydride mixtures were independent of the amount of solvent present in the system and concluded that ri and r3 in the kinetic scheme outlined above must be equal. This conclusion, which was also accepted by Baines and Bevington (13), enabled reactivity ratios for this copolymerization system to be calculated by use of the standard copolymer equation. Unfortunately, this is not a valid conclusion the results in Table II show that for conditions similar to those employed in the previous work, the styrene contents of the copolymers are imperceptibly affected by dilution of the system, even when r3 is five times greater or less than ri. 

Due to the difficulty of working with styrene-methacrylic anhydride copolymers, we have elected to determine reactivity ratios and cyclization constants from the compositions and structures of styrene-MMA copolymers derived from these copolymers. As is discussed in the experimental section it is possible to measure the styrene contents and the proportions of methoxy proton resonance occurring in three different areas (designated A, B and C) from the 1H-NMR spectra of S/MMA copolymers. The proportions of methoxy proton resonance observed in the A (F ), B (Fjj) and C (Fc) areas obey the following relationships in conventional styrene-MMA copolymers (6 7). 

The reactivity ratios for styrene-aryl methacrylate copolymerizations [79 — 27] differ significantly from those for the styrene-MMA system, so that copolymers derived from the aryl methacrylate copolymers should have different structures (sequence distributions) than conventional styrene-MMA copolymers of equivalent composition. In the system used to prepare styrene-methacrylic acid copolymers [75], the monomer reactivity ratios are comparable to those of the styrene-MMA system, but the stereochemical structure of the conventional copolymers and of those derived from the methacrylic acid copolymers might be expected to differ. In addition, change of the copolymerization solvent can alter the reactivity ratios for the styrene-methacrylic acid system. Finally, styrene-MMA copolymers derived from styrene-methacrylic anhydride copolymers [22] were expected to have especially interesting structures. The tendency of the anhydride units to become incorporated into the copolymers as cyclic units is very high and there is a great tendency for styrene and cyclic anhydride units in the co-... 

Using the r and tz values from Table 6-2, construct plots showing the initial copolymer composition as a function of the comonomer feed composition for the radical copolymerizations of methyl acrylate-methyl methacrylate and styrene-maleic anhydride. Are these examples of ideal or alternating copolymerization ... 

An appropriate formalism for Mark-Houwink-Sakurada (M-H-S) equations for copolymers and higher multispecies polymers has been developed, with specific equations for copolymers and terpolymers created by addition across single double bonds in the respective monomers. These relate intrinsic viscosity to both polymer MW and composition. Experimentally determined intrinsic viscosities were obtained for poly(styrene-acrylonitrile) in three solvents, DMF, THF, and MEK, and for poly(styrene-maleic anhydride-methyl methacrylate) in MEK as a function of MW and composition, where SEC/LALLS was used for MW characterization. Results demonstrate both the validity of the generalized equations for these systems and the limitations of the specific (numerical) expressions in particular solvents. 

Most comonomers differ from styrene in polarity and reactivity. A desired copolymer composition can be achieved, however, through utilization of copolymerization parameters based on kinetic data and on quantum-chemical considerations. This is done industrially in preparations of styrene-acrylonitrile, styrene-methyl methacrylate, and styrene-maleic anhydride copolymers of different compositions. 

Blends of styrenic pol5m ers (PS, high impact poly (styrene)) and biodegradable polymers (PLA) can be extruded and thermo-formed to produce very low density food service and consumer foam articles (29,31). The blends are compatibilized with styrene-based copolymers a styrene-maleic anhydride copol5mier, or a styrene methyl methacrylate copolymer. As blowing agent for foaming the compositions z-pentane is used. 

The composition and quantity of styrene-maleic anhydride (SMA) copolymer resins were varied in emulsion copolymerisation of methyl methacrylate and n-butyl acrylate conducted by both batch and semicontinuous processes. The resulting particle sizes and levels of coagulum were measured to determine the optimum conditions for incorporation of the SMA resins into the resulting latexes. A semicontinuous process, in which no buffer was included and the SMA was added in a second stage comonomer emulsion, was found to produce coagulum-free latexes. 13 refs. 

Various approaches have been undertaken for reactive compatibilization of poly-amide/ABS alloys. Maleic anhydride can be grafted to the ABS. Styrene maleic anhydride (SMA) copolymers have been employed as compatibilizers for polyamide/ABS blends. SMA and SAN copolymers are miscible when the AN and maleic anhydride (MA) contents are equal. The impact strength of these blends has been found to be sensitive to the amount and composition of the SMA copolymer. Addition of SMA to SAN/polyamide blends was found to enhance the tensile and impact properties of these blends. Imidized acrylic polymers have been used as compatibilizers for nylon-6/ABS blends. Glycidyl methacrylate and methyl methacrylate (GMA/MMA) copolymers are used as compatibilizing agents. The epoxide functionality in GMA is capable of reaction with polyamide end groups. GMA/MMA copolymers can be shown to be miscible with SAN over the range of AN content of ABS. Styrene/GMA copolymers have been reported to be used as compatibilizers for polymer pairs such as... 

Polymer reaction monitoring has been studied by Siesler [36]. Optical-fiber remote NIRS has been used to monitor the composition of methyl methacrylate (MMA) during the polymerization process, the copolymer reaction of styrene/maleic anhydride with 6-aminohexanoic acid, and the structural changes during the formation of PET film. 

At 26.7 mbar pressure 40% weight toss main product is 2,4-diphenyl thiophene at least 11 unidentified minor products CO2, H2O, butene, isobutene, dimethyl ketene, styrene, methacrylic acid, succinic-type 5-membered cyclic anhydrides Chlorotrifluoroethylene, styrene, HQ, chloropentafluoropropene, ethene, chloroethene, totuene, a-melhylstyiene, dimer and trimer structures with some unsaturation S1F4 (fiom reaction of HF with glass). Distribution of products varies with polymer composition CO, CO2, propene, isobutene, dimethyl ketene, acrolein, allyl alcohol, toluene, styrene, cl-methylstyrene, ethylbenzene, glycidol, glycidylmethacrylate product distribution depends on copolymer composition... 

In addition, borane-containing POs can be prepared by copolymerization of olefin with borane monomers or by hydroboration of polyolefins including unsaturated groups, such as olefin-divinylbenzene copolymer and olefin-diene copolymers. Many kinds of graft copolymers, such as poly-elhylene-gra/f-poly( vinyl alcohol), PE-g-PMMA, polypropylcnc-gra/f-poly-(maleicanhydride-co-styrene), polypropylene-gra/f-poly(methacrylic acid), polypropylene-gra/f-poly(vinyl alcohol), polypropylene-gra/f-polycaprolac-tone (PP-g-PCL), polypropylcnc-gra/f-poly(methyl methacrylate) (PP-g-PMMA), poly( ethylene-co-propylene)-gra/f-poly(methyl methacrylate) (EPR-g-PMMA), and poly(ethylene-co-propylene)-gra/f-poly(maleic anhydride-costyrene), have been synthesized by such a method resulting in controllable composition and molecular microstructures [63-66]. 

The rates of radical-monomer reactions are also dependent on considerations of steric effects. It is observed that most common 1,1-disubstituted monomers — for example, isobutylene, methyl methacrylate and methacrylo-nitrile—react quite readily in both homo- and copolymerizations. On the other hand, 1,2-disubstituted vinyl monomers exhibit a reluctance to ho-mopolymerize, but they do, however, add quite readily to monosubstituted, and perhaps 1,1-disubstituted monomers. A well-known example is styrene (Ml) and maleic anhydride (M2), which copolymerize with r — 0.01 and T2 = 0 at 60°C, forming a 50/50 alternating copolymer over a wide range of monomer feed compositions. This behavior seems to be a consequence of steric hindrance. Calculation of A i2 values for the reactions of various chloroethylenes with radicals of monosubstituted monomers such as styrene, acrylonitrile, and vinyl acetate shows that the effect of a second substituent on monomer reactivity is approximately additive when both substituents are in the 1- or cr-position, but a second substituent when in the 2- or /3-position of the monomer results in a decrease in reactivity due to steric hindrance between it and the polymer radical to which it is adding. 

Consider the copolymerization of 1,3-butadiene with the following monomers n-butyl vinyl ether, methyl methacrylate, methyl acrylate, styrene, vinyl acetate, acrylonitrile, maleic anhydride. If the copolymerizations were carried out using cationic initiation, what would be expected qualitatively for the copolymer compositions List the copolymers in order of their increasing butadiene content. Would copolymers be formed from each of the comonomer pairs Explain what would be observed if one used anionic initiation ... 

Since the Arimoto/Haven report of vinylferrocene polymerization was not detailed, this monomer was made and both its homopolymerization and its copolymerization were studied with a variety of organic comonomers such as styrene, methylacrylate, maleic anhydride, acrylonitrile, methyl methacrylate, N-vinylpyrolidone, vinyl acetate, and so on.31-38 The polymers were as well characterized as possible, and copolymer compositions were obtained versus feed mole ratios. 

A modified internal standard method has been developed to determine the compositions of terpolymers of maleic anhydride with styrene and a methacrylate or an acrylate. The method involves IR spectrophotometry of the samples. IR spectra are recorded by means of the potassium bromide technique. The IR analysis is based on integrated absorption of the anhydride and ester carbonyl groups. 9 refs. 

In addition to forming polymers with molecules of their own kind, many monomers can form copolymers with other monomers. The scale of possibilities is thus widely extended. In free radical polymerization, for example, styrene is converted to poly(styrene), methyl methacrylate to poly(methyl methacrylate), and vinyl acetate to poly(vinyl acetate). A mixture of styrene and methyl methacrylate gives poly(styrene-co-methyl methacrylate) even at the lowest conversions. From a mixture of styrene and vinyl acetate, on the other hand, practically pure poly(styrene) is first formed, and then, when the styrene is exhausted, almost pure poly(vinyl acetate). This is therefore a mixture (blend) and not a copolymer. Whereas stilbene, free-radically initiated, does not give a unipolymer, and maleic anhydride gives one of only low molecular weight, a mixture of both monomers leads to a copolymer of the composition 1 1. 

VFc has been copolymerized with common monomers such as styrene [19], methyl methacrylate [19], N-vinylpyrollidone [20], and acrylo nitrile [19]. The electron richness of VFc has been demonstrated in its copolymerization with maleic anhydride, in which an alternating composition of the copolymer was observed over a wide range of feed ratios [16, 19]. The Q and e values of VFc were determined. The value of e = -2.1 again emphasizes the electron rich nature of the vinyl group of VFc [21]. Therefore it looked rather hopeless to apply anionic initiators for the polymerization of VFc. 

---