Binary monomer system

In order to obtain GI profiles by copolymerization, two monomers (Mj and M2) satisfying the following conditions need to be employed  

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Copolymerization of VAc with Various Comonomers. The monomer mixtures used in our experiments were VAc as monomer Mi and AN, AA, MAA, acrylamide (AAm), maleic acid (MA), and fumaric acid (FA) as monomer M2 (33). All the ESR spectra obtained from the binary monomer systems containing vinyl ester and small amounts of M2... 

Obtained from Single and Binary Monomer Systems... 

These occluded macroradicals have been used to prepare block copolymers of styrene (17,19), acrylonitrile (20), vinyl acetate (21), and methyl methacrylate (22). This principal may be extended to binary monomer systems as well. An interesting example of this is shown by the highly alternating copolymers synthesized by charge transfer complex (CTC) copolymerization. 

ESR spectra of short-lived radicals in the liquid state. Applying it to the radical polymerization of AA, MAA, and itaconic acid (ITA), Fischer et al. <> -56) observed ESR spectra of monomer, dimer, and polymer radicals and discussed the conformations of these radicals in terms of the hyperfine splitting constants for their P-methylene protons. Ranby et al. 6i> extended its application to the radical polymerization of several monomers such as vinyl esters and butadiene and also to the copolymerization of binary monomer systems. However, the use of the thermal-redox radical-generating method has been chiefly restricted to reactions in aqueous solution. 

Organic peroxide-aromatic tertiary amine system is a well-known organic redox system 1]. The typical examples are benzoyl peroxide(BPO)-N,N-dimethylani-line(DMA) and BPO-DMT(N,N-dimethyl-p-toluidine) systems. The binary initiation system has been used in vinyl polymerization in dental acrylic resins and composite resins [2] and in bone cement [3]. Many papers have reported the initiation reaction of these systems for several decades, but the initiation mechanism is still not unified and in controversy [4,5]. Another kind of organic redox system consists of organic hydroperoxide and an aromatic tertiary amine system such as cumene hydroperoxide(CHP)-DMT is used in anaerobic adhesives [6]. Much less attention has been paid to this redox system and its initiation mechanism. A water-soluble peroxide such as persulfate and amine systems have been used in industrial aqueous solution and emulsion polymerization [7-10], yet the initiation mechanism has not been proposed in detail until recently [5]. In order to clarify the structural effect of peroxides and amines including functional monomers containing an amino group, a polymerizable amine, on the redox-initiated polymerization of vinyl monomers and its initiation mechanism, a series of studies have been carried out in our laboratory. 

Dielectric relaxation measurements of polyethylene grafted with acrylic acid(AA), 2-hydroxyethyl methacrylate (HEMA) and their binary mixture were carried out in a trial to explore the molecular dynamics of the grafted samples [125]. Such measurements provide information about their molecular packing and interaction. It was possible to predict that the binary mixture used yields a random copolymer PE—g—P(AA/HEMA), which is greatly enriched with HEMA. This method of characterization is very interesting and is going to be developed in different polymer/monomer systems. 

The corresponding monomer/micelle equilibria can be dealt with by the regular solution theory (RST), as shown in particular by Rubingh in 1979 (1). The application of this theory to numerous binary surfactant systems (2 - 4) has followed and led to a set of coherent results (5). 

Table 1. Total Monomer Concentrations and Micellar Compositions For a Binary SurFactant System at Various Deviations From Ideality...

In addition to the polymerization of dienes the versatility of NdP-based catalysts is exceptional regarding the number of different non-diene monomers which can be polymerized with these catalysts. Acetylene is polymerized by the binary catalyst system NdP/AlEt3 [253,254]. Lactides are polymerized by the ternary system NdP/AlEt3/H20 [255,256]. NdP/TIBA systems are applied in the copolymerization of carbon dioxide and epichlorhy-drine [257] as well as for the block copolymerization of IP and epichloro-hydrin [258]. The ternary catalyst system NdP/MgBu2/TMEDA allows for the homopolymerization of polar monomers such as acrylonitrile [259] and methylmethacrylate [260]. The quaternary system NdP/MgBu2/AlEt3/HMPTA is used for the polymerization of styrene [261]. 

The literature referring to catalyst preformation of binary catalyst systems is not addressed in this work. In this review the available studies on ternary catalyst systems are summarized. The available literature is discussed in the following two subsections Preformation without Monomer and Preformation in the Presence of Diene Monomers . 

In conclusion, the number of reports on the impact of the monomer/cata-lyst-ratio ( M/ Nd) on Mn are rather limited. Studies in which Mn was determined are only available for binary catalyst systems of the type NdCl3 3TBP/TIBA and for allyl Nd compounds. The data reported on these catalyst systems are in full compliance with requirement No. 3 for a living polymerization Linear dependence of Mn on monomer/catalyst-ratio at constant monomer conversion . Comparable studies with Nd carboxylates and other Nd precursors are missing. 

Equation (7.18) may be used to calculate the instantaneous composition of copolymer as a function of feed composition for various monomer reactivity ratios. A series of such curves are shown in Fig. 7.1 for ideal copolymerization, i.e., r r2 = 1. The term ideal copolymerization is used to show the analogy between the curves in Fig. 7.1 and Aose for vapor-liquid equilibria in ideal liquid mixtures. The vapor-liquid composition curves of ideal binary mixtures have no inflection points and neither do the polymer-composition curves for random copolymerization in which riV2 = 1. Such monomer systems are therefore called ideal. It does not in any sense imply an ideal type of copolymerization. 

Mathematical models of the frontal copolymerization process were developed, studied and compared with experimental data in [67, 90]. An interesting observation was that the propagation speed of the copolymerization wave was not necessarily related to the propagation speeds in the two homopolymerization processes, in which the same two monomers were polymerized separately. For example, the propagation speeds in the homopolymerization processes could be 1 cm/min in each, but in the copolymerization process, the speed could be 0.5 cm/min. Mathematical models of free-radical binary frontal polymerization were presented and studied in [66, 91]. Another model in which two different monomers were present in the system (thiol-ene polymerization) was discussed in [21]. A mathematical model that describes both free-radical binary frontal polymerization and frontal copolymerization was presented in [65]. The paper was devoted to the linear stability analysis of polymerization waves in two monomer systems. It turned out that the dispersion relation for two monomer systems was the same as the dispersion relation for homopolymerization. In fact, this dispersion relation held true for W-monomer systems provided that there is only one reaction front, and the final concentrations of the monomers could be written as a function of the reaction front temperature. 

Binary initiator systems of AlCl3/(-)-menthoxytriethyltin, AlCls-germanium, or AlCls-silicone for 265 polymerization are also known. N-Phenylmaleimide (66), a monomer with a C2 axis of symmetry, also gave an optically active homopolymer (267). Compound 267 can be optically active only if the main chain has in excess one of two enantiomeric trans structures, 268a and 268b. Helical structure has also been proposed for N-substituted maleimide polymers. 

Where an azeotropic system is possible at one specific composition of a three-component monomer system, then the three-component system is known as a partial azeotropic system, which reduces to a true azeotropic system at the specific composition. In such a case (Figure 22-4), other comonomer compositions lead to arrows arranged in a whirlpool manner about the azeotropic composition point. The arrows on the axes of the triangular plot give the compositions of the binary azeotropes. 

These observations point to the complex nature of the phase behavior of these systems and possible solubility maximum for the polymer in the binary fluid system consisting of monomer plus carbon dioxide. 

Eyring analyses (85-100°C) confirmed first-order kinetics in monomer concentration, and the activation parameters A/7 = 14.8(5) kcal/mol and = -7.6(2.0) cal/K mol were determined. A commonly accepted activated monomer mechanism for r ROP, applicable to these binary catalyst systems Ae+/ROH, is depicted in Scheme 28.7. 

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