scholarly journals Understanding the differential thermal behaviour of an oriented polymeric film, in response to the modulated differential scanning calorimetry variables, for determination of the degree of crystallinity

2015 ◽  
Author(s):  
Rohan Ambardekar ◽  
Hrushikesh Karandikar ◽  
Adrian Kelly ◽  
Phil Caton-Rose ◽  
Phil Coates ◽  
...  
2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.


2021 ◽  
Vol 11 (14) ◽  
pp. 6324
Author(s):  
Rita Brzezińska ◽  
Agata Górska ◽  
Magdalena Wirkowska-Wojdyła ◽  
Ewa Ostrowska-Ligęza ◽  
Joanna Bryś

The chemical composition of green coffee beans depends on the number of parameters, such as coffee cherry processing methods, used. The quality of roasted coffee is related to the certain substances that developed during the roasting process and that are responsible for the organoleptic properties. The main objective of this study was an investigation of the thermal behaviour and the fatty acids profile of green and roasted Brazilian Santos coffee beans. The glass transition temperature was measured using modulated differential scanning calorimetry (MDSC). The thermal behaviour of coffee samples was evaluated by means of thermogravimetry (TG) and first derivative thermogravimetry (DTG). The oxidative stability and kinetic parameters were characterized with the use of differential scanning calorimetry (DSC). According to the TG and DTG curves, coffee samples showed different behaviour of thermal degradation in the atmosphere of oxygen and nitrogen. Our research shows that the thermal properties and fatty acids profile did not change during the roasting process.


2006 ◽  
Vol 58 (5) ◽  
pp. 209-214 ◽  
Author(s):  
Subramoney N. Moorthy ◽  
Lena Andersson ◽  
Ann-Charlotte Eliasson ◽  
Stalin Santacruz ◽  
Jenny Ruales

2021 ◽  
pp. 004051752110533
Author(s):  
Martina Vikova ◽  
Shinichi Sakurai ◽  
Aravin Prince Periyasamy ◽  
Hidekazu Yasunaga ◽  
Miroslava Pechočiaková ◽  
...  

In this work, ultraviolet (UV) sensible metallocene isotactic polypropylene (miPP) filaments were produced with different drawing ratios and various concentrations of photochromic pigment. The effects of pigment concentration and drawing ratio on the chromatic properties and the structural modification for the miPP filaments were studied extensively by differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS/WAXS) measurements. The change in melting temperature and the polymeric structures, such as lamellar thickness, long period and degree of crystallinity of miPP with the addition of a UV sensible pigment into miPP and the drawing process, were evaluated. The results show that the pigment concentration and the drawing ratio influence the inner structure of miPP filaments. Finally, our investigation shows that SAXS and also WAXS are appropriate to determine the lamellar thickness and the degree of crystallinity established by the DSC approach. This work attempts to correlate the results of lamellar thickness, the degree of crystallinity and the higher-order structure of the polymer acquired by DSC as well as X-ray diffraction (XRD) techniques in order to develop an appropriate approach to find the influence of pigment concentration and drawing ratio on miPP filaments.


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