scholarly journals Evaluation of the recrystallization kinetics of hot-melt extruded polymeric solid dispersions using an improved Avrami equation

2014 ◽  
Vol 41 (9) ◽  
pp. 1479-1487 ◽  
Author(s):  
Xin Feng ◽  
Xingyou Ye ◽  
Jun-Bom Park ◽  
Wenli Lu ◽  
Joe Morott ◽  
...  
Keyword(s):  
Solid Dispersions ◽  
Avrami Equation ◽  
Recrystallization Kinetics ◽  
Polymeric Solid ◽  
Kinetics Of ◽  
Hot Melt

Recrystallization of 304SS during and after High Strain Rate Deformation

2013 ◽  
Vol 753 ◽  
pp. 403-406
Author(s):  
Adam S. Taylor ◽  
Peter D. Hodgson
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Austenitic Stainless Steels ◽  
Avrami Equation ◽  
Recrystallization Process ◽  
Hollomon Parameter ◽  
Softening Mechanism ◽  
Recrystallization Kinetics ◽  
Kinetics Of ◽  
Shape Changes

During the hot working of austenitic stainless steels the shape of the flow curve is strongly influenced by the strain rate. Low strain rate deformation results in flow curves typical of dynamic recrystallization (DRX) but as the strain rate increases the shape changes to a ‘flat-top’ curve. This has traditionally been thought to indicate no DRX is taking place and that dynamic recovery (DRV) is the only operating softening mechanism. Examining the work-hardening behaviour and corresponding deformation microstructures showed this is not the case for austenitic stainless steel, as clear evidence of dynamic recrystallization process can be seen. The post-deformation recrystallization kinetics can be modelled using a standard Avrami equation with an Avrami exponent, n, of 1.15. With an increasing value of the Zener-Hollomon parameter it was found that the kinetics of recrystallization become less strain rate sensitive until at the highest values (highest strain rates/lowest temperatures) the recrystallization kinetics become strain rate insensitive.

scholarly journals Tablet Development for a Hydroscopic Drug Using Solid Dispersion

2020 ◽  
Vol 9 (1) ◽  
pp. 23-28
Author(s):  
O. A. Terenteva ◽  
V. A. Vainshtein ◽  
E. V. Flisyuk ◽  
Yu. E. Generalova
Keyword(s):  
Solid Dispersion ◽  
Solid Dispersions ◽  
Medical Science ◽  
Technological Properties ◽  
Peg 6000 ◽  
Science In Russia ◽  
Shear Mixing ◽  
Children And Young Adults ◽  
Kinetics Of ◽  
Hot Melt

Introduction. Traumatic brain injury is a damage to the brain from an external mechanical force, possibly leading to permanent or temporary impairment of cognitive, physical, and psychosocial functions. It is a leading cause of death and disability among children and young adults. In connection with the above, the objective of developing new, more effective nootropic and antiasthenic drugs in the framework of restorative neurology is considered as one of the priority tasks of medical science in Russia.Aim. Development the composition and technology of tablets containing a hygroscopic substance using solid dispersions.Materials and methods. The pharmaceutical substance of a diethylaminoethanol derivative having antihypoxic, neuroprotective, adaptogenic and antioxidant effects is a hygroscopic powder. PEG 6000 was chosen as a matrix for solid dispersion production. Solid dispersions were obtained by high shear mixing and hot-melt extrusion. The technological properties of granulate and the quality indicators of the tablets were determined according to the methods described in the State Pharmacopoeia of the Russian Federation (14th edition).Results and discussion. The lactose mixed with the DEAE-PEG composition alloy improve the technological properties of granulate.Conclusion. A decrease water-absorbing ability of DEAE was achieved using PEG 6000 as a matrix carrier. The increase PEG content did not lead to a significant change in the kinetics of the release of DEAE from tablets.

scholarly journals Morphology and crystallization kinetics of Rubber-modified Nylon 6 Prepared by Anionic In-situ Polymerization

2020 ◽  
Vol 27 (1) ◽  
pp. 204-215
Author(s):  
Hongkai Zhao ◽  
Dengchao Zhang ◽  
Yingshuang Li
Keyword(s):  
Crystallization Kinetics ◽  
In Situ Polymerization ◽  
Good Description ◽  
Nylon 6 ◽  
Avrami Equation ◽  
Infrared Analysis ◽  
Chain Segment ◽  
The Impact ◽  
Kinetics Of

AbstractIn this work, we modified nylon 6 with liquid rubber by in-situ polymerization. The infrared analysis suggested that HDI urea diketone is successfully blocked by caprolactam after grafting on hydroxyl of HTPB, and the rubber-modified nylon copolymer is generated by the anionic polymerization. The impact section analysis indicated the rubber-modified nylon 6 resin exhibited an alpha crystal form.With an increase in the rubber content, nylon 6 was more likely to generate stable α crystal. Avrami equation was a good description of the non-isothermal crystallization kinetics of nylon-6 and rubber-modified nylon-6 resin. Moreover, it is found that the initial crystallization temperature of nylon-6 chain segment decreased due to the flexible rubber chain segment. n value of rubber-modified nylon-6 indicated that its growth was the coexistence of two-dimensional discoid and three-dimensional spherulite growth. Finally, the addition of the rubber accelerated the crystallization rate of nylon 6.

Effect of Arenga Pinnata “Ijuk” Fiber as Nucleating Agent on Crystallization Kinetics of Impact Polypropylene Copolymer

2018 ◽  
Vol 923 ◽  
pp. 56-60 ◽  
Author(s):  
Mochamad Chalid ◽  
Evana Yuanita ◽  
Ghiska Ramahdita ◽  
Jaka Fajar Fatriansyah
Keyword(s):  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Nucleating Agent ◽  
Avrami Equation ◽  
Nucleating Agents ◽  
Impact Polypropylene Copolymer ◽  
Kinetics Of

Impact Polypropylene Copolymer (IPC) is one of the PP type which is widely used. IPC was made with addition of ethylene in PP which decreases PP crystallinity. Many efforts have been made to improve the properties of PP crystallinity by addition of nucleating agents. In this study, we use Arenga Pinnata “Ijuk” fiber as PP nucleating agent. In order to determine the effect of “Ijuk” fiber as nucleating agents in kinetics aspect, we used DSC measurement based on Avrami equation. The results showed that the addition of ijuk decreases crystallizationhalf timeand dimension of crystal growth which indicate the effects of “Ijuk” fiber as a nucleating agent.

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