Copolymers influence of composition

Ye, W.P, Du, F.S., Jin, W.H. et al. (1997) In vitro degradation of poly(caprolactone), poly(lactide) and their block copolymers influence of composition, temperarnre and morphology. Reactive Functional Polymers, 32,161-168. 

Giri L, Roslaniec Z, Ezquerra T A and Balta Calleja F J (1997) Microstructure and mechanical properties of PET-PCc block copolymers Influence of composition, structure, and physical aging, J Macromol Sci Phys B36 335-343. 

Abstract This chapter gives an overview of the research on the self-assembly of amorphous block copolymers at different levels of hierarchy. Besides the influence of composition and topology on the morphologies of block copolymers with linear, cyclic and branched topologies blends of block copolymers with low molecular weight components, other polymers or block copolymers and nanoparticles will also be presented. 

Influence of Composition and Crystallizable Block Position within ABC Triblock Copolymers... 

In semi dilute (c>c, [B] = 0.3-0.5 mole.l- ) or dilute (c< c, [B] = 10-2 mole.l- -) solution, Kp is significantly greater for copolymers than for the model compounds whatever the solvent is. For semi-dilute solution in a given solvent, the complex influences of composition, unit distribution and tacticity do not result in definite trends on K, values, as illustrated in table 6 by some representative Kj data related to keto-2-picolyl structures at 25°C. 

An early study of the influence of composition heterogeneity on the physical properties of copolymers was undertaken by Nielson (4), but to the knowledge of the authors, there have been no similar Investigations involving tin-based polymers. In this work a range of different acrylic co- and terpolymers has been prepared and the effects of composition and composition distribution on the physical and performance-related properties of the polymers in their native state and In paints have been examined. 

Fig. 6a. Influences of composition (ST-content) and chain architecture of ST-MMA copolymers upon Rf, observed under Pattern (1) shown in Fig. 5.

Fig. 6. Influence of composition on the modulus-temperature behavior of perfectly alternating block copolymers [52]...

Some interesting results have been obtained by Russian scientists [320, 321] who studied the influence of composition inhomogeneity on some service properties and supermolecular structures of copolymers. Two samples of copolymers of butyl acrylate with methacrylic acid were synthesized which had a similar average... 

Fig. 5 Influence of composition on the phase transition temperature (VPTT) of two different copolymer microgel series. Reprinted from [74] with permission. Copyright 2008 American Chemical Society...

Pistel KF, Bittner B, Koll H, Winter G, Kissel T. Biodegradable recombinant human erythropoietin loaded microspheres prepared from linear and star-branched block copolymers Influence of encapsulation technique and polymer composition on particle characteristics. J Control Release 1999 59 309-325. 

The influence of composition on the Tg of these copolymers is shown in Figure 5 which also includes the data for the series of HPAMs. Roth the copolymer and the HPAM data appear to define a similar Tg vs. composition relationship which deviates substantially from that of Klein and Heitzmann. Further, the curve for these systems appears to extrapolate to a Tg value of 106° for PAA, which agrees well with some literature values for this homo-polymer This focuses attention on the Tg values for PAA obtained by DSC in this work (124°C) and by Klein and Heitzmann (126°C). The reason for this discrepancy has not yet been established. 

Since the knowledge about molar mass determination using viscosimetry and determination of the coil dimensions is of fundamental importance for technical problem solving, these are the main topics of this book. It will give detailed case studies and theoretical background about the different independent variables, like concentration, molar mass, quality of the solvent, chemical nature of the polymer, polyelectrolyte character, composition of copolymers, influence of the substitution pattern for renewable raw materials and the degree of branching. 

Furfural is a resin former under the influence of strong acid. It will self-resinify as well as form copolymer resins with furfuryl alcohol, phenoHc compounds, or convertible resins of these. Conditions of polymerization, whether aqueous or anhydrous, inert or oxygen atmosphere, all affect the composition of the polymer. Numerous patents have issued relating to polymerization and to appHcations. Although the resins exhibit a degree of britdeness, they have many outstanding properties a number of appHcations are discussed under "Uses."... 

Fig. 3. Influence of vinyl alcohol—vinyl acetate copolymer composition on melting temperature (56), where A represents block copolymers B, blocky...

Table 3 Influence of Radiation Dose on the Copolymer Composition and the Swelling Degree...

The influence of radiation dose on the polymer composition and the swelling degree of (pAM-DAEA-HCl) are shown in Table 3. The results show that the percent of acrylamide in the copolymer is higher than that of the amine. This can be attributed to smaller reactivity ratios of monomers of diallylammonium salts relative to acryl-... 

Any understanding of the kinetics of copolymerization and the structure of copolymers requires a knowledge of the dependence of the initiation, propagation and termination reactions on the chain composition, the nature of the monomers and radicals, and the polymerization medium. This section is principally concerned with propagation and the effects of monomer reactivity on composition and monomer sequence distribution. The influence of solvent and complcxing agents on copolymerization is dealt with in more detail in Section 8.3.1. 

The influence of penultimate units on the kinetics of copolymerization and the composition of copolymers was first considered in a formal way by Merz et al and Ham.8 They consider eight propagation reactions (Scheme 7.2). 

The influence of selectivity in the initiation, termination or chain transfer steps on the distribution of monomer units within the copolymer chain is usually neglected. Galbraith et a .u provided the first detailed analysis of these factors. They applied Monte Carlo simulation to examine the influence of the initiation and termination steps on the compositional heterogeneity and molecular weight distribution of binary and ternary copolymers. Spurting et a/.250 extended this... 

The precipitation polymerization literature is reviewed with particular attention to the influence of particle formation and growth, autoaccelerating polymerization rates, and copolymer composition drift on polymer reactor design. 

Table V. Influence of Siloxane Graft Molecular Weight and Composition on Surface Composition of PMMA-g-PSX Copolymers by Variable Angle XPS (ESCA) (Copolymers 5 wt.% PSX)...

NM Franson, NA Peppas. Influence of copolymer composition on non-Fickian water transport through glassy copolymers. J Appl Polym Sci 28 1299-1310, 1983. 

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