Influence of Citric Acid on the Properties of Glycerol-Plasticised Cornstarch Extrusion Blends

2007 ◽  
Vol 15 (7) ◽  
pp. 545-552 ◽  
Author(s):  
Wang Ning ◽  
Yu Jiugao ◽  
Han Chunmei

Melt extrusion was used to prepare glycerol-plasticised dry thermoplastic starch (DTPS) in a single-screw extruder. Glycerol combined with water-plasticised starch (TPS) was studied as a standard. Citric acid (CA) was used to accelerate the plasticization of DTPS. Scanning electron microscopy revealed that residual granules existed in DTPS and the plasticisation of DTPS could be enhanced by CA. Rheological studies proved that CA decreases the shear viscosity and improves the fluidity of TPS and DTPS. It was also proved by Fourier transform infrared spectroscopy that starch and glycerol could form strong hydrogen bonds in the presence of CA. With increasing CA content, the rigid and fragile DTPS materials became more flexible, with a high tensile strength. Dynamic mechanical thermal analysis proved that CA could decrease the glass transition temperature of TPS and increase the interaction between glycerol and starch. Finally, the water absorption of DTPS and TPS were also measured.

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.


2012 ◽  
Vol 550-553 ◽  
pp. 1513-1521
Author(s):  
Sirirat Thothong ◽  
Klanarong Sriroth ◽  
Rattana Tantatherdtam ◽  
Amnat Jarerat

To improve the miscibility of native rice starch granules and poly(butylene adipate-co-terephthalate)(PBAT), rice starch was hydrolyzed by a mixture of α-amylase and amyloglucosidase. The obtained porous rice granular starch was then mechanically blended with PBAT by single screw extruder. Many pits and holes on the surface of starch granules were observed by scanning electron microscopy (SEM). The rough surface of the rice starch granules improved the compatibility of the polymers in the blends, which consequently increased the tensile strength and the elongation at break. In addition, SEM also revealed that the porous granules were homogeneously distributed in the polymer matrix with no appearance of gaps.


1994 ◽  
Vol 9 (2) ◽  
pp. 286-291 ◽  
Author(s):  
Kunsong Ma ◽  
Alain C. Pierre

Bi—(Pb)—Sr—Ca—Cu—O superconductors were synthesized by sol-gel processing from nitrates by complexation with citric acid. Their grain growth and sintering above 800 °C were studied by Scanning Electron Microscopy (SEM) and Brunauer, Emmett, Teller (BET) porosimetry. The sintering was limited by anisotropic grain growth, and microcracks in 2212 phase grains were created due to the formation of 2223 phase.


2012 ◽  
Vol 573-574 ◽  
pp. 1156-1160
Author(s):  
Hong Yu Shi ◽  
Hui Liu ◽  
Shu Lan Guo

This study is focusing on the protein sand binder on the performance of wet sand, and explores the protein binding mold sand reusability and reclamation. With thermal analysis and scanning electron microscopy testing, and by comparing with other traditional technologies, the experimental result shows that it is a more environmental friendly.


2020 ◽  
Vol 985 ◽  
pp. 86-90
Author(s):  
Andi Muhammad Anshar ◽  
Sengo Kobayashi ◽  
Satoshi Okano

The surface wettability of biomaterials influences on osteoblast behavior and bone formation. In this research, the variation of wettability of nacre by heat treatments was examined. Plates of the nacre were fabricated from shells of the Akoya pearl oyster. The specimens were heated at 100, 200, 300, 400, 500, and 600 °C. Characterizations of the specimens during and after heat treatments were carried out using scanning electron microscopy, X-ray diffractometry, and thermogravimetry-differential thermal analysis. The water contact angle (WCA) of the specimen was measured to evaluate wettability. The color of nacre changed from iridescent color to brownish weak-iridescence by the heating at and over 300 °C. The nacre heated at and over 300 °C became brittle because organic substances in nacre, which acts as the glue between the aragonite platelets were evaporated by the heating. The WCA of the specimen was decreased with increasing heating temperature, which should be related to the decrease in the number of organic substances in nacre by the heating.


2008 ◽  
Vol 575-578 ◽  
pp. 941-946
Author(s):  
Hong Yan Tang ◽  
Ji Hui Wang ◽  
Guo Qiang Gao ◽  
Wen Xing Chen

Fiberglass continuous strand mat(CSM)/poly(urethane-isocyanurate) composites were formed by SRIM process, treated under different conditions and then characterized based on dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) ,transmission electron microscopy (TEM) and the mechanical property tests. The results show that the mechanical properties of the composites could be increased with improving the degree of microphase separation. At a given temperature (120°C), the degree of microphase separation is the highest for 4h and decreases gradually with prolonging treatment time. For a given time (4h), the well microphase-separated morphology is obtained and the degree of microphase mixing is increased at 120°C and 140°C treatments, respectively. The degree of microphase separation of the composites decreases with enhancing the temperature to 140°C.


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