Homopolymers structure-based method

CA s policy for naming acetylenic, acrylic, methacrylic, ethylenic, and vinyl polymers is to use the source-based method, and source-based representation is used to depict the polymers graphically thus, a synonym for polyethylene is polyethylene and not poly(1,2-ethanediyl) a synonym for polypropylene is polypropylene, and poly(vinyl alcohol) is named ethenol homopolymer although ethenol does not exist. Thus, these polymers are named and represented structurally by the source-based method, not the structure-based method. 

Polystyrene is the name of a homopolymer made from the single monomer styrene. When the name of a monomer comprises two or more words, the name should be enclosed in parentheses, as in poly(methyl methacrylate) or poly(4-bromostyrene) to identify the monomer more clearly. This method can result in several names for a given polymer thus, poly(ethylene glycol) , poly(ethylene oxide) and poly(oxirane) describe the same polymer. Sometimes, the name of a hypothetical monomer is used, as in poly(vinyl alcohol) Even though a name like polyethylene covers a multitude of materials, the system does provide understandable names when a single monomer is involved in the synthesis of a single polymer. When one monomer can yield more than one polymer, e.g. 1,3-butadiene or acrolein, some sort of structural notation must be used to identify the product, and one is not far from a formal structure-based name. 

It should be noted that the majority of the methods of synthesis of block and graft copolymers yield, in addition to the copolymer, fractions of the associated homopolymers to a greater or lesser extent. Therefore in order to determine the composition and the structure of the copolymer, it is first of all necessary to separate it from any homopolymer which may be present. This separation is usually based upon solubility differences between the different components (203). Although the turbidimetric titration may be very useful for analytical purposes (157), nevertheless it gives samples too small for further examination preparative methods, which are based on fractional precipitation, selective extraction or selective precipitation should be preferred. It is beyond the scope of this review to discuss these separation methods the reader is referred to existing literature concerning this subject (51). 

C-NMR spectroscopy has also been used to investigate the composition of DADMAC copolymers [38, 45-47]. Copolymers with acrylamide (AAM) have been extensively studied. Based on the chemical shifts in the 13C-NMR spectra of the homopolymers of DADMAC [17-19] and AAM [48-50], the copolymer spectra can be analyzed. Specifically from two likely chad structures (m/r) in PAAM and six different diad structures (r/m, c/t) in PDADMAC, eight different diad structures can be expected for the copolymers. A detailed NMR analysis has therefore been carried out in order to determine the copolymer compositions. The reactivity ratios obtained were found to be in good agreement with the results from other methods, such as potentiometric titration or elementary analysis, provided that the DADMAC in the copolymer was below approximately 70% [38]. 

Synthetic peptide-based polymers are not new materials homopolymers of polypeptides have been available for many decades and have only seen hmited use as structural materials [5,6]. However, new methods in chemical synthesis have made possible the preparation of increasingly complex polypeptide sequences of controlled molecular weight that display properties far superior to ill-defined homopolypeptides [7]. Furthermore, hybrid copolymers, that combine polypeptide and conventional synthetic polymers, have been prepared and combine the functionality and structure of peptides with the processabihty and economy of polymers [8,9]. These polymers are well suited for applications where polymer assembly and functional domains need to be at length scales ranging from nanometers to microns. These block copolymers are homogeneous on a macroscopic scale, but dissimilarity between the block segments typically results in microphase heterogeneity yield-... 

The development of PPE synthetic chemistry makes the synthesis of PPEs with various structures possible. Recently, PPE-based polymers with different topological structures including linear random copolymers, block copolymers, star polymers, miktoarm polymers, and brush and hyperbranched polymers have been synthesized. Among them, linear homopolymers or random copolymers of PPEs are perhaps the most studied. Different block copolymers with AB, ABA, and ABC architectures have been synthesized by controlled ROP. By the combination of ROP of PPE with other controlled polymerization methods, such as living radical polymerization, or click chemistry, more complex architectures including miktoarm, comb, or graft copolymers can be synthesized. The richness of structures has allowed the convenient adjustment of material properties of PPE for biomedical applications. 

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