Macromers polymers

Martens P, Anseth KS. Characterization of hydrogels formed from acrylate modified poly(vinyl alcohol) macromers. Polymer 2000 41 7715-7722. 

Kim S S and Lee Y M, Synthesis and properties of semi-interpenetrating polymer networks composed of j -chitin and polyfethylene glycol) macromer . Polymer,... 

D Angelo S, Galleti P, Maglio G, Malinconico M, Morelli P, Palumbo R and Vignola M C (2001) Segmented poly (ether-ester-amide)s based on poly (L,lrlactide) macromers. Polymer 42 3383-3392. 

Zhao, S. P. and Xu, W. L. 2010. Thermo-sensitive hydrogels formed from the photocrossUnkable polyp-seudorotaxanes consisting of P-cyclodextrin and pluronic F68/PCL macromer. /. Polym. Res., 17 503-510. 

The study of acid-base interaction is an important branch of interfacial science. These interactions are widely exploited in several practical applications such as adhesion and adsorption processes. Most of the current studies in this area are based on calorimetric studies or wetting measurements or peel test measurements. While these studies have been instrumental in the understanding of these interfacial interactions, to a certain extent the interpretation of the results of these studies has been largely empirical. The recent advances in the theory and experiments of contact mechanics could be potentially employed to better understand and measure the molecular level acid-base interactions. One of the following two experimental procedures could be utilized (1) Polymers with different levels of acidic and basic chemical constitution can be coated on to elastomeric caps, as described in Section 4.2.1, and the adhesion between these layers can be measured using the JKR technique and Eqs. 11 or 30 as appropriate. For example, poly(p-amino styrene) and poly(p-hydroxy carbonyl styrene) can be coated on to PDMS-ox, and be used as acidic and basic surfaces, respectively, to study the acid-base interactions. (2) Another approach is to graft acidic or basic macromers onto a weakly crosslinked polyisoprene or polybutadiene elastomeric networks, and use these elastomeric networks in the JKR studies as described in Section 4.2.1. 

Common examples of the high Tg macromers are based on polystyrene or polymethylmethacrylate (PMMA) polymers of sufficiently high molecular weight to have a high T (typically on the order of 70-100°C as measured by differential scanning calorimetry) and also to make them immiscible with the acrylic polymer backbone once the solvent or heat has been removed. Typical molecular weight of the polystyrene or PMMA macromers is on the order of 5000-10,000 Da. Their generic structure can be pictured as in Fig. 13 (shown there for polystyrene). 

A copolymerizable group, such as an acrylate (R = H) or methacrylate (R = methyl), on one end of the molecule, and the high Tg polymer on the other end characterize the macromer. A chemically inert group, such as oxyethylene may be present to connect the two parts of the macromer. Macromers have been synthesized by different methods and some are commercially available. 

When a single macromer is incorporated into a polymer chain, the result is a three armed star , as shown in Fig. 5.12 a). When numerous macromers are incorporated into a single backbone, the result is a comb , as shown in Fig. 5.12 b). In the case, where macromers are produced in situ, the macromers themselves can be branched and the resulting polymers can be branched in a complex fashion, as shown in Fig. 5.12 c). 

Finally, some polymerisations can be directed such that the final oligomer or polymer contains two or more reactive end groups capable of extended polymerisation with different monomers. These materials are named telechelic macromers or telechelic polymers. 

Thermoset polymers (sometimes called network polymers) can be formed from either monomers or low MW macromers that have a functionality of three or more (only one of the reagents requires this), or a pre-formed polymer by extensive crosslinking (also called curing or vulcanisation this latter term is only applied when sulfur is the vulcanising or crosslinking agent.) The crosslinks involve the formation of chemical bonds — covalent (e.g., carbon-carbon bonds) or ionic bonds. 

Although there are other unsaturated compounds that will undergo addition-elimination with free radicals, the benzyl ketene acetal XIV appears to be the most active double bond as far as rate of addition is concerned and the most efficient as far as regards to the extent of elimination is concerned. A comparison with the list of chain transfer agents listed in the Polymer Handbook (23) indicated that only the sulfur compounds appear to be more effective than XIV. Hydrolysis of the end-capped oligomer gives a macromer that is terminated with a carboxylic acid group. 

Polymers containing one reactive end group are often referred to as macromolecular monomers or macromers. They can be represented as... 

Macromers are then short polymers, which contain an active end group. This end group can be a site of unsaturation, heterocycle, or other group that can further react. Macromers are usually designed as intermediates in the complete synthesis of a polymeric material. These macromers can be introduced as side chains (grafts) or they may serve as the backbones (comonomer) of polymers. The macromers can also act as separate phases. 

Macromers have been used to produce thermoplastic elastomers. Generally, the backbone serves as the elastomeric phase while the branches serve as the hard phases. These structures are often referred to as comb -shaped because of the similarity between the rigid part of the comb and its teeth and the structure of these graft polymers. 

Block copolymers are also produced using such macromers. Again, the various units of the polymer can be designed to act as needed with hard or/soft, or hydrophilic or hydrophobic, or other combinations. In addition, these macromers generally have two active functional groups that allow polymerization to occur. 

Macromers can also be used as cross-linkers between already formed polymers when both ends are active. These functional groups could be either two vinyl ends or two Lewis acids or bases such as two hydroxyl or amine groups. Interpenetrating polymer networks (IPNs) and related structures such as dendrites and stars can also be formed using macromers. 

Macromers with propylene oxide. Hydroxypropyl (organosolv) lignin (HPL) is a low molecular weight (pre)polymer with a number average molecular... 

A more recent development, MACROMER , a new tool that expands our capability for synthesizing controlled polymer structures, will also be discussed. 

The use of MACROMER technology is another synthetic tool that the polymer scientist has in being able to prepare a wide variety of new types of polymer structures which could be of some potential commercial interest, such as ... 

Functionally terminal polymers are valuable material intermediates. The di- and polyfunctional varieties (telechelic polymers) have found theoretical (e.g., model network) and commercial (e.g., liquid rubber) applications (1, ). On the other hand, macromolecules with a functional group at one chain end (semitelechelic polymers) have been used to prepare novel macromolecular monomers (Macromers ), as well as block and graft copolymers ( -8). 

Title Dithiocarbonate-Containing Macromers and Polymers Derived Therefrom... 

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