Copolymerization of MAH with

If reactivity ratios are particularly disparate then it is possible to form a block copolymer from a batch polymerization. Thus the copolymerization of MAH with S by NMP or RAFT with excess S provides P(MAH-o/f-S)-i(> ocA -PS. There is a similar outcome in other copolymerizations which show a strong alternating tendency such as S with maleimides e.g. or AN. The... 

Spontaneous copolymerization of MAH with strong electron donors like 5,6-dihydro-1,4-dioxin [975], 1,1-dimethoxyethene [976], alkyl vinyl sulfides [977], phenyl vinyl sulfide [978] or styrene [979]. 

The effects of solvent on reactivity ratios and polymerization kinetics have been analyzed for many copolymerizations in terms of this theory.98 These include copolymerizations of S with MAH,"7 118 S with MAA,112 S with MMA,116 117 "9 121 S with HEMA,122 S with BA,123,124 S with AN,103415 125 S with MAN,112 S with AM,11" BA with MM A126,127 and tBA with HEMA.128 It must, however, be pointed out that while the experimental data for many systems are consistent with a bootstrap effect, it is usually not always necessary to invoke the bootstrap effect for data interpretation. Many authors have questioned the bootstrap effect and much effort has been put into finding evidence both for or against the theory.69 70 98 129 "0 If a bootstrap effect applies, then reactivity ratios cannot be determined by analysis of composition or sequence data in the normal manner discussed in Section 7.3.3. 

The copolymerization of butadiene with MAH yields an unsaturated 1 1 alternating copolymer while the copolymerizations of CPD with MAH and with NPMI yield saturated 1 2 copolymers. The copolymerization of the CPD-MAH adduct with MAH and the copolymerization of the CPD-NPMI adduct with NPMI yield the same copolymers as are obtained from CPD and MAH and CPD and NPMI, respectively, The CPD copolymerizations may actually proceed through the rapid formation of the adducts, followed by their copolymerization with MAH and NPMI, respectively. 

The same hydroxy-functional pEB was reacted with 4-cyano-4-[(thiobenzoyl) sulfanyl] pentanoic acid to produce a macroinitiator for a RAFT copolymerization (Scheme 25) [134].Klumperman et abused this RAFT agent to initiate the polymerization of St or the copolymerization of St with MAh. 

EPDM-g-MAH A graft copolymerization of EPDM with maleic anhydride... 

Gabara and Porejko proposed that the heterogeneous radical catalyzed graft copolymerization of MAH onto LDPE film suspended in acetic anhydride at 80-110 C proceeded through the coupling of PE macroradicals with poly(maleic anhydride) (poly-MAH) radicals. 

The present investigation was undertaken in an attempt to correlate the proposed participation of cationic intermediates in the radical-induced homopolymerization of MAH with the use of MAH polymerization conditions in the graft copolymerization onto PE. 

Olaj et al. [63] expand the Mayo mechanism focusing on the chemistry of the dimer intermediate. They performed UV spectroscopic measurements (315-365 nm) on polymerizing styrene and presented evidence to support the formation of two stereoisomers of the Mayo dimer (DHa and DHb). They suggest that both isomers are consumed during styrene polymerization. Possible consumption pathways are copolymerization, chain transfer, and formation of initiating radicals by MAH with monomer. They believe that only the axial phenyl isomer DHa is capable of generating initiating radicals by reaction with monomer. 

There are a few thousand patents on functionalization of polyolefines, and the amount of published papers in open literature is growing fast. Without doubt, the most studied monomer is maleic anhydride (MAH). This is because it contains a functionality for radical reactions and also a cyclic anhydride for other reactions. Copolymerization of polar monomers with ethylene or propylene could be used to improve the polarity of PP or PE, but due to the sensitivity of the Ziegler-type of catalysts used during polyolefin polymerization this is difficult. For this reason, graft copolymerization in the melt is an attractive route to acquire modified polymers and conserve most of the original properties of the materials. 

The unusual aspects of the BPO-MAH reaction in the presence of PE and the effect of DMF thereon, are clearly shown when compared with the results when DMF is present during the reaction of BPO with acrylic acid in the presence of PE (Table III). The absence of crosslinking in the presence of acrylic acid and the failure of DMF to rediice the carboxyl content of the PE are consistent with the conventional radical character of the graft copolymerization of acrylic acid onto PE. 

The tendency of MAH to form copolymers is so strong, that it can even be copolymerized with thiophene, its 2-methyl or 3-methyl derivatives [1017-1019], furan and 2-methylfuran [1020,1021] all stable aromatic heterocycles, that are reluctant to homopolymerize or copolymerize with other monomers. The repeating units consist of structures with 2,5-linkages (furan, thiophen) and 2,3-linkages across the methyl-substituted derivatives (Figure 12). 

Li and coworkers [51] developed another strategy for the synthesis of block copolymers, prepared via one-pot polymerizations. For example, RAFT copolymerization of maleic anhydride (MAh) and St with a molar ratio of 1 9 was performed at 60 °C. Basically, the polymerization involves two stages, first, the copolymerization of St and MAh resulted in an alternating copolymer (stage 1). After the complete consumption of MAh, propagation reactions of St continued to produce the diblock copolymer RB-8. 

In this section wc consider systems where the radical formed by propagation can eyclizc to yield a new propagating radical. Certain 1,4-dicncs undergo cyclocopolymerization with suitable olefins. For example, divinyl ether and MAH are proposed to undergo alternating copolymerization as illustrated in Scheme 4.19.167 These cyclo-copolymerizations can he quantitative only for the case of a strictly alternating copolymer. This can be achieved with certain electron donor-electron acceptor pairs, for example divinyl ether-maleic anhydride. 

The PE radical is formed as a result of hydrogen abstraction by the MAH excimer, as shovm in eq. (2), or a radical from the catalyst. The coupling of the PE radical with the MAH excimer or the poly-MAH radical results in graft copolymerization. 

Ethylene can be copolymerized with methyl MAH [1108] (Figure 13). Esterification of the resulting copolymer with alcohols yields head-to-head copolymers of acrylates and methacrylates [1108]. 

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