Block Multipolymers

The kinetic data from this experiment is shown in Fig. 3.1.7, resulting in the RlO-1 product (Section 3.1.4.2). Its GPC trace is shown in Fig. 3.1.11, which indicates a material with a relatively high molecular weight and a reasonable PDI of 1.97. When the reactor product was coagulated in water with KOH, the coagulum can be drawn into a fibrous material. This is probably due to the development of microcrystalline domains of potassium acrylate in the polymer, as evidenced by a melting transition at 47°C. 

Aside from the PS-PBA type of emulsion FRRPP product introduced in Section 3.2, it is worth mentioning the promise of the formation of other emulsion FRRPP block copolymer products, such as PMMA-PBA. 

In a recent work, formation of block multipolymers from radicalized VDC copolymer particulates has been demonstrated (Caneba et al., 2008). Using the two-stage stirred-tank reactor system (Fig. 4.2.1), recipes and conditions were generated using high-throughput experimentation methods. From cloudpoint experiments (Table 1.1.3), it has already been established that the solvent for the VDC polymerization via FRRPP process is azeotropic MEK/i-butanol. 

An example product is a diblock called RBI-232 made of a VDC copolymer (96 wt% VDC, 6 wt% Zonyl TA-N) block with a butyl acrylate-Vaf-glycidyl methacrylate block. The reactor product solution was fractionally precipitated, and 

A related product called RBI-200 was made its detailed recipe and procedure are presented in Table 4.2.1. 

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In this chapter, implications of the FRRPP phenomenon are presented in terms of unique polymerization production system systems. Control over the rate of polymerization has been exploited, resulting in the formation of new types of statistical and block multipolymers. 

In the following subsections, the author presents some of the methods used to carry out multistaged block multipolymer formation. 

In order for block multipolymer formation to occur uniformly from the first-stage polymer radicals with this method, the second-stage monomer should be able to diffuse fast enough in order to minimize core-shell polymer formation. Also, the second monomer set should form a second block that would have properties that are distinct from the first block. This is not easy if there is substantial first block monomer left in the reactor. However, for certain cases, this is quite feasible. 

When properly done, it is therefore possible to implement multistage block multipolymer formation from the FRRPP process. This is especially true if the main first-stage monomer material is a gas or a volatile liquid, such as VDC. 

Product VDC-Zonyl TA-N copolymers are in the form of fine particulate (Fig. 3.2.6), which were removed from the reactor through a 1/8 in. copper or stainless steel line that is immersed in ice-water bath. This kept the polymer radicals active for block multipolymer formation. 

Fig. 4.2.2 High-throughput experimentation 10-atm glass tube reactors used in the eariy stage block multipolymer formation...

The number of two-polymer, multipolymer, and multimonomer systems reported in the scientific and patent literature continues to rise without an adequate nomenclature to describe the several materials. This chapter is divided into three parts. (1) A proposed nomenclature system which uses a short list of elements (polymers or polymer reaction products). These elements are reacted together in specific ways by binary operations which join the two polymers to form blends, grafts, blocks, crosslinked systems, or more complex combinations. (2) The relationship between the proposed nomenclature and the mathematics of ring theory (a form of the new math9 ) is discussed. (3) A few experimental examples now in the literature are mentioned to show how the new nomenclature scheme already has been used to discover new multipolymer systems. 

Another area which is growing rapidly is multicomponent polymer systems. As noted in the section on structure and properties, block polymers should contribute special properties to multipolymer systems. 

Today, one of the most challenging areas concerning phase separated multipolymer materials relates to the prediction of the domain sizes. Various preparation techniques yield very different dimensions. Much theoretical work on domain size prediction has been done on block polymer, as mentioned above, but not other multipolymer systems. 

Polymer comprising two or more polymer networks which are at least partially interlaced on a molecular scale (Figure 1.16) but not covalently bonded to each other and cannot be separated rmless chemical bonds are broken [206,411]. A mixture of two or more preformed polymer networks is not an IPN. An IPN may be further described by the process by which it is synthesized e. g. when an IPN is prepared by a process in which the second component network is polymerized following the completion of polymerization of the first component network, the IPN may be referred to as a sequential IPN. In contrast, a process in which both component networks are polymerized concurrently, the IPN may be referred to as a simultaneous IPN. An IPN is distinguished from other multipolymer combinations, such as polymer blends, blocks, and grafts, in two ways (1) an IPN swells, but does not dissolve in solvents and (2) creep and flow are suppressed. 

Block and graft copolymers are obtained from two consecutive and separate polyreactions, and so are called multistep polymers. These concepts can, in principle, also be extended to multipolymers (terpolymers and quaterpolymers, etc.). 

Still another reactive block copolymer product, called RB 1-215, contained butyl acrylate (BA) in the second block (B-block) (Caneba et ah, 2008). The same Stage 1 (formation of A-block) was used as in RBI-200 and RBI-201. Typically, there were three cycles to the Stage 2 reaction. Cycle 1 contained 340 ml NMP, 34 g MMA, 42.5 g GMA, 8.5 g BA and Cycle 2 contained 16 g MMA, 16 g Zonyl TA-N. Cycle 3 was a heating cycle only without addition of any new monomers. Figure 4.3.2 depicts the overall procedure used to produce the reactive RB 1-215 ABC triblock multipolymer. Detailed recipe and procedure are also presented in Table 4.3.2. 

Polymeric surfactants from multipolymers seem to be possible from blocky (tapered- or step-block) and segmental block stractures. It has also been possible... 

The outstanding behavior of multipolymer cdmbinations usually derives from the phase-separated nature of these materials. In fact, polymer blends, blocks, grafts, and IPNs are interesting because of their complex two-phased nature, certainly not in spite of it. Aspects of phase continuity, size of the domains, and molecular mixing at the phase boundaries as well as within the phase structures all contribute to the mechanical behavior patterns of these multicomponent polymer materials. 

In the era of the mid-1960s, three distinct multipolymer combinations were recognized polymer blends, grafts, and blocks. Although interpenetrating polymer networks, IPNs, were prepared very early in polymer history, and already named by Millar in 1960, they played a relatively low-key role in polymer research developments until the late 1960s and 1970s. 

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