Differential scanning copolymer

The compositional distribution of ethylene copolymers represents relative contributions of macromolecules with different comonomer contents to a given resin. Compositional distributions of PE resins, however, are measured either by temperature-rising elution fractionation (tref) or, semiquantitatively, by differential scanning calorimetry (dsc). Table 2 shows some correlations between the commercially used PE characterization parameters and the stmctural properties of ethylene polymers used in polymer chemistry. 

ATBN - amine terminated nitrile rubber X - Flory Huggins interaction parameter CPE - carboxylated polyethylene d - width at half height of the copolymer profile given by Kuhn statistical segment length DMAE - dimethyl amino ethanol r - interfacial tension reduction d - particle size reduction DSC - differential scanning calorimetry EMA - ethylene methyl acrylate copolymer ENR - epoxidized natural rubber EOR - ethylene olefin rubber EPDM - ethylene propylene diene monomer EPM - ethylene propylene monomer rubber EPR - ethylene propylene rubber EPR-g-SA - succinic anhydride grafted ethylene propylene rubber... 

Figures la and lb. Differential Scanning Calorimetry Results of the Second Cooling Runs for (a) Solution Blended and (b) Extrusion Blended PLA/EVAc Homopolymers and Copolymers.

Figure 2. Comparison of the Differential Scanning Calorimetry (DSC) thermograms of the homopolymer HB and various block copolymers to that of the LDPE. Weight of each polymer sample is indicated in the parentheses. The instrument range is 2 mcal/s for all the runs.

Block copolymers with PS and a polymethacrylate block carrying a liquid crystalline group, PS-b-poly 6-[4-(cyanophenylazo)phenoxy]hexyl methacrylate, were successfully prepared in quantitative yields and with relatively narrow molecular weight distributions (Scheme 5) [18]. The thermotropic liquid crystalline behavior of the copolymers was studied by differential scanning calorimetry. 

One such property, as has been demonstrated (see [26]), is the change in partial heat capacity of the copolymer solution upon the heat-induced conformational transition of macromolecules. Such a change was detected by high-sensitivity differential scanning calorimetry (HS-DCS). The DSC data for the NVCl/NVIAz-copolymers synthesized at initial comonomer ratios of 85 15 and 90 10 (mole/mole) are given as thermograms in Fig. 4. 

Rytter et al. reported polymerizations with the dual precatalyst system 14/15 in presence of MAO [30]. Under ethylene-hexene copolymerization conditions, 14/MAO produced a polymer with 0.7 mol% hexene, while the 15/MAO gave a copolymer with ca. 5 mol% hexene. In the mixed catalyst system, the activity and comonomer incorporation were approximate averages of what would be expected for the two catalysts. Using crystallization analysis fractionation (CRYSTAF) and differential scanning calorimetry (DSC) analysis, it was concluded in a later paper by Rytter that the material was a blend containing no block copolymer [31],... 

In this study, mechanical properties of emulsion copolymers of viityl acetate and butyl aciylate, which consisted of a nonionic emulsifier (30 mol ethoxylated nottyl-phenol), an oligomeric stabilizator, and ammonium persulfate or potassium persulfate as initiators by changing monomer ratios from 90 10 to 10 90 for VAc BuA, were determined by differential scanning calorimeter. 

Keywords Copolymers, differential scanning calorimeter, emulsion homopolymers, latexes, oligomeric stabilizator, polymerization... 

In this study, mechaiucal properties of emulsion copolymers of VAc and BuA were determined by differential scanning calorimeter (DSC). 

QO2— ). Glass transition temperatures (Tg s) of copolymers I and IV were determined by the use of a differential scanning calorimeter. The samples were heated at 10 C/minute In air, to 200 C, then cooled and reheated. Glass transition data was taken from the "second heating". 

In copolymers of group B the Curie transition appears in the differential scanning calorimetric curve as a broad peak, extending over a temperature interval which narrows down with increasing VF2 content. The transition... 

Oxidation of mixtures of 2,6-disubstituted phenols leads to linear poly(arylene oxides). Random copolymers are obtained by oxidizing mixtures of phenols. Block copolymers can be obtained only when redistribution of the first polymer by the second monomer is slower than polymerization of the second monomer. Oxidation of a mixture of 2,6-di-methylphenol (DM ) and 2fi-diphenylphenol (DPP) yields a random copolymer. Oxidation of DPP in the presence of preformed blocks of polymer from DMP produces either a random copolymer or a mixture of DMP homopolymer and extensively randomized copolymer. Oxidation of DMP in the presence of polymer from DPP yields the block copolymer. Polymer structure is determined by a combination of differential scanning calorimetry, selective precipitation from methylene chloride, and NMR spectroscopy. 

Differential Scanning Calorimetry. Some structural information is provided by the thermal behavior of the polymer. The homopolymer of DPP crystallizes when heated above the glass transition temperature. A crystallization exotherm at the appropriate temperature therefore indicates the presence of DPP blocks, either as the homopolymer or in a block copolymer. 

Figure 3. Differential scanning calorimeter traces of 1 1 DMP-DPP copolymers...

Solvent effects including 2-methyl-l,3-dioxepane (MDOP), as a solvent, on the propagation kinetics of methyl acrylate (MMA) have been investigated using the PLP-SEC technique (PLP = pulse laser polymerization) <2005MI267>, and the composition of dioxolane-dioxepane copolymers has been studied by IR and differential scanning calorimetry (DSC) <2004PB349>. 

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