Multipolymers

In the late 1960s a new class of AN copolymers and multipolymers was introduced that contain >60% acrylonitrile. These are commonly known as barrier resins and have found thek greatest acceptance where excellent barrier properties toward gases (5), chemicals, and solvents are needed. They may be processed into bottles, sheets, films, and various laminates, and have found wide usage in the packaging industry (see Barrier polymers). 

TPs come in greater variety than TSs. They also tend to be more readily to specialty compounding as copolymers, multipolymers, alloys and blends, often customized for cost-effective adaptation to specific application requirements. Unlike TSs, they are in most cases reprocessable without serious losses of properties. 

The multipolymer enzymatic resolution of soluble polymer-supported alcohols 42 and 43 was achieved using an immobilised lipase from Candida Antarctica (Novozym 435). The R-alcohol was obtained in enantiomerically pure form (>99% ee) after its cleavage from the poly(ethylene) glycol (PEG) scaffold . The achiral hydantoin- and isoxazoline-substituted dispirocyclobutanoids 47 were produced using both solution and solid-phase synthesis <00JOC3520, OOCC1835>. 

Acrylic-based multipolymer (15) Acryloid KM 581 Rohm Haas... 

Copolymers of acrylonitrile and methyl acrylate and terpolymers of acrylonitrile, styrene, and methyl methacrylate are used as bamer polymers. Acrylonitrile copolymers and multipolymers containing butyl acrylate, ethyl aciylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methaciylate. vinyl acetate, vinyl ethers, and vinylidene chlonde are also used in bamer films, laminates, and coatings. Environmentally degradable polymers useful in packaging are prepared from polymerization of acrylonitrile with styrene and methyl vinyl ketone. 

Han H, Janda KD, Multipolymer-supported substrate and ligand approach to the Sharpless asymmetric dihydroxylation, Angew. Chem., Int. Ed. Engl., 36 1731-1733, 1997. 

Toy PH, Reger TS, Janda KD, Soluble polymer bound cleavage reagents A multipolymer strategy for the cleavage of tertiary amines from REM resins, Org. Lett., 2 2205-2207, 2000. 

A Proposed Generalized Nomenclature Scheme for Multipolymer and Multimonomer Systems... 

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. 

The above examples use the abstract element symbols Pi, Gi2, etc. Briefly let us show how this system will operate with real monomers, polymers, and multipolymer combinations, using chemical notation instead of the elements but retaining the binary operation notation. 

Tables. The value of the proposed system lies principally in its capability of depicting very complex multipolymer combinations. These tables, unlimited in size, join combinations of elements systematically. Tables IV and V provide examples. Each binary operation has a table and all of the elements can appear in any table. The rows are reacted with the columns in that order. For example, in Table V, Pi at the left of the row is reacted with P2 at the top of the column to synthesize Gi2.

From a chemical point of view, it may not be known if P3 in Equation 19 will react with Fx or P2 or both. Further tables can be set up, giving the isomeric structures of the multipolymer grafts. From a mathematical or chemical point of view, each element in the new tables will be... 

Because of the variance in multipolymers, an exact chemical structure is not possible. To differentiate between different asphaltenes, the methodology leading to an average structure is necessary. 

Hydrogels are another type of polymer structure comprised of a hydrophilic cross-linked network that swells in water. They can exist as homopolymers, copolymers, or multipolymers and are generally biocompatible and have low degradation. Hydrogels can be produced with a wide range of swelling... 

Gelva [Solutia], TM for a family of acrylic multipolymer products designed for high-performance, pressure-sensitive adhesive applications where skin adhesion, high temperature and/or diffi-cult-to-adhere-to surface are involved. Provided for both solvent and water based grades. 

Fig. 1 Nanofiber modification strategies. In step 1, many polymer and solution properties will affect the size, stability, and reactivity of nanofihers in the final mat, including multipolymer blending strategies, incorporation of soluble factors/drugs/spheres, and/or loading concentrations. In step 2, during spinning, the ambient conditions and voltage applied must be tailored for each polymer source and can be dictated by the nature of the collector or the number of jets employed simultaneously. In step 5, the as-spun mat can be modified by various crosslinking techniques to stabilize the polymers or, in the case of soluble or carrier polymers, these can be leached out by subsequent liquid washes...

Baker BM et al (2009) Fabrication and modeling of dynamic multipolymer nanofibrous scaffolds. J Biomech Eng 131(10) 101012... 

Another option is the use of both solid-supported versions of the catalyst and the co-oxidant. The Toy group in Hong-Kong has developed a multipolymer system for the TEMPO-catalyzed alcohol oxidation in which both the pre-catalyst and the co-oxidant are attached to a polymer. As it was clearly impossible to use two insoluble supported reagents, the idea was to use an insoluble polymer in conjunction with a soluble one. An insoluble polymer-supported diacetoxyiodosobenzene (PSDIB), an analog of 10, and a soluble polymer-supported TEMPO were used,... 

A multipolymer version of the aerobic TEMPO oxidation of alcohols in the presence of Cu(II) was also developed in the Toy group using immobilized TEMPO and polymer-supported 2,2 -bipyridine, which form the oxidative organometalhc complex with copper [31],... 

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