Differential scanning calorimetry polymer blends studied using

The phenomenon of physical aging in polymers has received considerable attention, but relative few studies of physical aging in polymer/polymer mixtures have appeared in the literature. Most of these have made use of differential scanning calorimetry and enthalpic data to assess physical aging behavior in blends. Tables 13.1 and 13.2 provide a list of the most important systems investigated to date. 

In a study by Nanda and co-workers, the thermal properties of the blend were evaluated using differential scanning calorimetry (DSC). The Tm of P(3HB-co-3HV) copolymer was reported as 152 °C and for PLA, it was reported as 170 °C. The for the blend was found to be in between these two polymers. Miscibility of any polymer can be determined by evaluating the Tg. A single Tg indicates the miscibility of the polymer. One Tg that corresponded to PLA was reported and the Tg for P(3HB-co-3HV) copolymer was poorly observed. They also reported that when the content of P(3HB-co-3HV) copolymer was increased, reduction in Tg from 60 °C to 45 °C was observed. The same observation was reported by Richards et al. and Modi et al. ... 

Thermal analysis techniques are used to study the properties of polymers, blends and composites and to determine the kinetic parameters of their stability and degradation processes.Here the property of a sample is continuously measured as the sample is programmed through a predetermined temperature profile. Among the most common techniques are thermogravimetry (TG) and differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) and dielectric spectroscopy are essentially extensions of thermal analysis that can reveal more subtle transitions with temperature as they affect the complex modulus or the dielectric function of the material. 

Surender Rajendran, Mahendran Arunjunai, Thamaraichelvan A., Alam Sarfaraz, and Vijayakumar Chinnaswamy Thangavel. Curing studies of bisphenol A based bismaleimide and Cloisite 15A nanoclay blends using differential scanning calorimetry and model-free kinetics. J. Appl. Polym. Sci. 128 no. 1 (2013) 712-724. 

Automotive industry waste provided another idea for a study [10]. Recycled plastics from bumpers are being applied in several areas, even as new bumpers [11, 12]. Thermal analysis was applied to the material used in discarded car bumpers, which came from standard grade automobiles of different brands. The recycled polymer composition was a polymeric blend of PP, ethylene-propylene-diene monomer (EPDM) and high-density polyethylene (HOPE). Differential scanning calorimetry (DSC) analysis (Figure 2.5) confirmed the presence of PP, and indicated HDPE and EPDM as ingredients in the formulation of car bumpers. 

In this preliminary study, extracted willow xylan was not immediately available for use in blending studies. As a result, native, partially acetylated birch xylan and a synthetically acetylated elm xylan were obtained from the sample collection of Professor T. E. Timell, an emeritus faculty member at our institution. Blends of these polymers with cellulose esters and bacterial polyesters were typically prepared by mbcing solutions of the respective polymers dissolved in either dimethylformamide (DMF) or water followed by evaporation in a vacuum oven at 10S°C yielding a thin film. A thermoplastic bacterial co-polyester (poly(hydroxybutyrate)) containing 30% hydroxyvalerate content) was purchased from the Aldrich Chemical Company (cat. no. 28,248-0). The glass transition temperature (Tg) of each polymer and blend was determined using a TA Instruments 2920 differential scanning calorimetry (DSC) instrument. 

The use of Xe NMR to probe phase separation in polymer blends has been particularly useful for probing miscibility in those polymer blends in which the components have comparable glass transition temperatures, making it difficult, if not impossible, to study miscibility by using methods such as differential scanning calorimetry. There are plans to use this NMR method to measme domain size in phase-separated polymer blends. 

Modulated differential scanning calorimetry was used to study miscible polymer blends. The blends studied... 

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