Copolymerization characteristics

Several appHcations have been found for bis(2-chloroethyl) vinylphosphonate as a comonomer imparting flame retardancy for textiles and specialty wood and paper appHcations. Its copolymerization characteristics have been reviewed (76,109). This monomer can be hydrolyzed by concentrated hydrochloric acid to vinylphosphonic acid, polymers of which have photoHthographic plate coating utiHty (see Lithography). It is also an intermediate for the preparation of an oligomeric vinylphosphonate textile finish, Akzo s Fyrol 76 [41222-33-7] (110). 

This study examines the synthesis of acrylated lignin derivatives using IEM, and the copolymerization characteristics of these derivatives with methylmethacrylate (MMA) and styrene (S). 

Copolymerization. The copolymerization of butadiene-styrene with alkyllithium initiator has drawn considerable attention in the last decade because of the inversion phenomenon (12) and commercial importance (13). It has been known that the rate of styrene homopolymerization with alkyllithium is more rapid than butadiene homopolymerization in hydrocarbon solvent. However, the story is different when a mixture of butadiene and styrene is used. The propagating polymer chains are rich in butadiene until late in reaction when styrene content suddenly increases. This phenomenon is called inversion because of the rate of butadiene polymerization is now faster than the styrene. As a result, a block copolymer is obtained in this system. However, the copolymerization characteristic is changed if a small amount of polar solvent... 

These investigations were concentrated on the vinyl ester of Versatic 911, the acid derived from C8-Ci0 olefins. This product will be referred to further as W 911. The copolymerization of VV 911 with vinyl acetate, especially the emulsion copolymerization, was studied extensively. This paper describes the copolymerization characteristics of VV 911, a process developed for latex manufacture, and the reasons for its excellent reproducibility. 

It was foimd that PS-h-PCHD block copolymers can be prepared in hydrocarbon solvents using s-BuIi as the initiator without the presence of any additive [34]. Efficient crossover reactions were obtained from either PSLi (Scheme 12 route A) or PCHDLi (Scheme 12 route B). Using potassium/naphthalene as a difunctional initiator PS-fo-PCHD-fc-PS and PCHD-fo-PS-fo-PCHD were prepared. However, the molecular weight distributions were rather broad, and side reactions were observed when copolymers with high CHD contents were required. To avoid this problem several additives were tested in order to improve the copolymerization characteristics. The best results were obtained with dimethoxyethane, DME, or... 

With vinylidene chloride, VC A was incorporated into the copolymer only to a small extent (Figure 3). It is assumed that the unfavorable difference between the Q values of the monomers (QVCi2 — 0.2 and QVca = 0.007) as well as the sensitivity of the VCA radical to chain transfer with vinylidene chloride hinder a higher incorporation of VCA. Since the copolymer precipitated during the polymerization, this system could not be used for evaluation of copolymerization characteristics. 

This study was undertaken to see if improved tire cord adhesive systems could be developed using poly (DHA-co-4VP) and/or poly(DHA-co-NVP) materials. Since these copolymer systems were new and since previously published Q and e values for DHA (8), 4VP (9), and NVP (10) suggested poor copolymerizability between the monomer sets, a detailed copolymerization study of these monomer pairs was needed. In summary, this study was initiated to determine copolymerization characteristics, i.e. reactivity ratios, of DHA-co-4VP and DHA-co-NVP, to characterize briefly some of the physical and chemical properties of the resultant materials, and to evaluate select copolymers in tire cord adhesive systems. 

Cqpolymerization of MCM with traditional monomers is the main technique of metal insertion into a polymer chain, and it is more widely used than their homopolymerization. However, ocpolymerization laws in such systems are difficult to analyze because of their raultiparameter dependence of the kinetics and copolymerization characteristics on the process, parameters such as pH, solvent nature and even concentration ratio (30). The metal-containing giroup in MCM is, as a rule, an electron-donor substituent (scheme Q-e). The copolymerization yields complexes of different comonomers, effecting the polymer composition and structure. In our view, the most remarkable one is cqpolymerization of transition metal diacrylates with MMA, styrene, etc. (37), as well as vinylpyridine and vinylimidazole MX complexes and formation of ternary copolymers of the following composition (38) ... 

With Ziegler-Natta systems, ongoing developments target further product improvements (e.g. control of molecular mass distribution or copolymerization characteristics) and the increase of activity retaining at least the already achieved levels of stereospecificity and morphology. Enhanced activities will enable a flexible operation of high capacity plants due to technically feasible reduced residence times (i.e. short transitions at product changes). 

In an experiment to determine if this type of catalyst may have properties required for industrial applications, Jolly et cd. carried out a polymerization at 80°C with catalyst 3. The results showed that this particular catalyst exhibited an activity of 50,750 Kg PE/mol Cr/hr with a constant polymerization rate for an extended period, thus indicating very beneficial polymerization properties for commercial applications. In addition, catalyst 6 was evaluated in ethylene/1-hexene copolymerization experiments. In neat 1-hexene an elastomeric material was isolated with an activity of 40,000 Kg PE/mol Cr/ hr under polymerization conditions described in Table 3.12, while in toluene containing 20 vol% 1-hexene, an ethylene/1-hexene copolymer was isolated with a DSC melting point of 112°C, suggesting a LLDPE material (i.e., density of ca. 0.91-0.92 g/cc) was produced with a homogeneous branching distribution, which is expected based on the polydispersity value of 1.58 for the same catalyst in an ethylene homopolymerization experiment. This copolymerization data also shows that this particular catalyst has necessary copolymerization characteristics for industrial applications. 

These monomers could easily be considered as additional examples of vinyl ether type monomers. Thinking in this vein, these monomers 22 would be expected to exhibit homo and copolymerization characteristics similar to the vinyl ethers—i.e., homopolymerize poorly with free-radical initiators and copolymerize readily with MA. 

The principle melting features are determined by the octene content in the hard block, as incorporated by the hard catalyst, and can thus be varied. This relationship is demonstrated with Samples 13 and 17-19 made using precatalysts 3, 26, 27, and 28 (Figure 24). In these copolymers, the composition of the soft block is constant, but the octene content in the hard block is varied according to the copolymerization characteristics of the hard catalysts. Precatalysts 3 and 26 both incorporate very little octene and give OBCs,... 

Atomic polymerization is not polymerization in the conventional sense, because the molecular structure of the monomers is not retained in the polymer. For instance, the glow discharge polymers of acetylene and benzene are very much alike. Their copolymerization characteristics are nearly identical. When N2 and H2O are added to benzene or acetylene, considering that one molecule of benzene is equivalent to three molecules of acetylene in glow discharge polymerization, nearly identical polymers are formed.(19)... 

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