Blends with Partial Miscibility

In case (a), the blend is quenched from the homogeneous melt at temperature To to a temperature Ti outside the two phase region, where the system crystallizes as a single phase. In case (b), the melt is quenched outside the miscibility gap to a temperature below the melt-crystallization curve within the single phase region owing to the crystallization of one component, the concentration of the amorphous polymer in the melt 

Another interesting phenomenon, which can be observed in blends with miscibility gap, is the occurrence of interface crossing crystallization [46]. In conditions of phase separation, two phases with different concentrations of the crystallizable component are present and, due to differences in the number density of heterogeneous nuclei, the phase with a higher content 

Similar effects were found by analyzing the overall crystallization kinetics from the melt at the same the crystallization half-time ty of the blend increased exponentially with increasing concentration of the amorphous component. The temperature dependence of the spherulite growth rate (G) and kinetic constant was then examined according to Equation (10.13) 

A notable composition dependence of the melting parameters and crystallinity degree was reported for all PEO/PMMA blends, with a melting behavior that was affected by the crystallization conditions and molecular 

Several examples of miscible blends with both crystallizable components have been reported for polyolefins and olefin copolymers, such as high density polyethylene (HDPE)/linear low density polyethylene (LLDPE), HDPE/very low density polyethylene (VLDPE), LDPE/ VLDPE, and PP/PB, with the occurrence of concurrent crystallization and/or co-crystallization phenomena [19, 

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SMA PC blend. This blend (Arloy , Arco) contained SMA grafted with polybutadiene as the impact modifier. The properties of SMA/PC blend were similar to ABS/PC blend with slightly higher heat distortion temperatures (107 to 117°C) but comparable impact strength (> 500 J/m). However, it was discontinued from the market due to unfavorable economics relative to ABS/PC blend. The partial miscibility between the styrene-maleic anhydride and polycarbonate accounts for the adequate compatibility of this blend as evidenced by the high level of tensile and impact strengths. 

Nishio, Y., Koide, T., Miyashita, Y., Kimura, N., Suzuki, H.J. Water-Soluble Polymer Blends with Partially Deacetylated Chitin A Miscibility Characterization. Appl. Polym. Sci. 37, 1533-1538 (1999)... 

Poly(8-caprolactone) (PCL), on the other hand, is a semi-ciystaUine biodegradable polymer. This material is commonly used as plasticizer. The P(3HB)/ PCL blend exhibited partial miscibility, however, the elongation at break was increased about 81 % in comparison with pure P(3HB) [43]. 

The phase behavior of blends of TMOS and SAN was investigated by means of optical cloud point measurements and DSC by Pfefferkom et al. (2012). The blends display partial miscibility with an upper critical solution temperature (UCST). Moreover, the SAN/TMOS blends show pronounced miscibUity-window behavior, i.e., the UCST depends strongly on SAN copolymer composition. 

In 50 50 mixtures small spherulites were present in as-cast blends but were lost on heating and cooling. Indications were found that there was little crystallinity in 50 50 mixtures or blends with 75 wt % CAB on long annealing at 4 "C, a result said to be consistent with partial miscibility. 

Thermal properties of thermoplastic starch composites reinforced with pehuen husk showed the potential of this bioliber as an excellent reinforcement for composite materials. TPS composites showed a good interaction between the fibers and the plasticized starch matrix due to the natural affinity between husk and starch in the pehuen seed. TPS/PLA/PV A blend showed partial miscibility or co-continuous phase and TPS/PLA/PV A composites presented also discontinuities at the biofiber-polymeric matrix interface. The incorporation of biofiber improved the thermal stability of the composites, increasing the initial decomposition temperature. The biofiber hinders the out-dififusion of the volatile molecules (e.g., glycerol), retarding the decomposition process of starch composites. On the other hand, the degree of crystallinity of composites decreases when pehuen husk content increases (Castano et al. 2012). 

Oxirane Process. In Arco s Oxirane process, tert-huty alcohol is a by-product in the production of propylene oxide from a propjiene—isobutane mixture. Polymer-grade isobutylene can be obtained by dehydration of the alcohol. / fZ-Butyl alcohol [75-65-0] competes directly with methyl-/ fZ-butyl ether as a gasoline additive, but its potential is limited by its partial miscibility with gasoline. Current surplus dehydration capacity can be utilized to produce isobutylene as more methyl-/ fZ-butyl ether is diverted as high octane blending component. 

Epoxidized oils were also used to modify PLA Ali et ah (2009) reported that its use as a plasticizer to improve flexibility. Thermal and scanning electron microscope analysis revealed that epoxidized soybean oil is partially miscible with PLA. Rheological and mechanical properties of PLA/epoxidized soybean oil blends were studied by Xu and Qu (2009) Epoxidized soybean oil exhibited a positive effect on both the elongation at break and melt rheology. Al-Mulla et al. (2010b) also reported that plasticization of PLA (epoxidized palm oil) was carried out via solution casting process using chloroform as a solvent. The results indicated that improved flexibility could be achieved by incorporation of epoxidized palm oil. 

When two polymers interact or react with each other, they are likely to provide a compatible, even a miscible, blend. Epoxidized natural rubber (ENR) interacts with chloro-sulfonated polyethylene (Hypalon) and polyvinyl chloride (PVC) forming partially miscible and miscible blends, respectively, due to the reaction between chlorosulfonic acid group and chlorine with epoxy group of ENR. Chiu et al. have studied the blends of chlorinated polyethylene (CR) with ENR at blend ratios of 75 25, 50 50, and 25 75, as well as pure rubbers using sulfur (Sg), 2-mercapto-benzothiazole, and 2-benzothiazole disulfide as vulcanizing agents [32]. They have studied Mooney viscosity, scorch... 

Blends of PE, of PMMA, andofPVA(O) with HPL of varying molecular weight produce two-phase materials. Blends of HPL with PVA (> 0) exhibit at least partial miscibility. 

Compatibilizer ABS copolymers have been prepared via an emulsion polymerization process. These copolymers have been functionalized with glycidyl methacrylate (GMA). The functionalized copolymers are blended PBT. Characterization by thermal mechanical analysis indicates that PBT is partially miscible with ABS and the glycidyl grafted ABS (48). 

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