Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism

Soft Matter ◽  
2014 ◽  
Vol 10 (27) ◽  
pp. 4990-5002 ◽  
Author(s):  
Alina K. Higham ◽  
Christopher A. Bonino ◽  
Srinivasa R. Raghavan ◽  
Saad A. Khan
Keyword(s):  
Real Time ◽  
Ionic Gelation ◽  
Structure Property ◽  
Alginate Hydrogel ◽  
Structure Property Relationships ◽  
System P

In siturheological techniques are used to characterize and investigate the structure–property relationships for a two-step photoinitiated alginate crosslinking system.

Structure-Property Relationships of Poly(Butylene Terephthalate)/Polyolefin Blends

1998 ◽  
Vol 18 (1-2) ◽  
pp. 17-30 ◽  
Author(s):  
D.S. Lee ◽  
J.K. Doo ◽  
B. Kim ◽  
J. Kim
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Structure Property ◽  
Melt Mixing ◽  
Butylene Terephthalate ◽  
Polyolefin Blends ◽  
Structure Property Relationships ◽  
Acrylic Ester ◽  
Discrete Phase

Abstract Structure-property relationships of poly(butylene terephthalate) (PBT) / polyolefin (PO) (80/20) blends modified by a reactive compatibilizer, ethylene-acrylic ester-glycidyl methacrylate terpolymer (BAG), were investigated as part of studies on toughening of PBT. POs used for the study were ethylene propylene rubber (EPR), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), whose deformabilities were different at room temperature. It was observed that the particle size of PO in the discrete phase was the smallest when the EAG content was 8~12 wL%. Shear viscosity of the blends increased as the particle size was decreased. It seems that the morphology and rheological properties of the blends were affected by graft copolymers formed in situ from EAG and PBT during melt mixing. Brittle-tough transition of impact strength of the PBT/EPR/EAG blends was observed when the EAG content was increased from 0 to 4 wt% at room temperature. However, blends of PBT/LDPE/EAG and PBT/HDPE/EAG showed brittle-tough transition with increasing the EAG content from 8 wt% to 12 wt%. It is postulated that toughening of the PBT depends on the deformability of the discrete PO particle as well as its size.

In situ characterization of Cu–Co oxides for catalytic application

2015 ◽  
Vol 177 ◽  
pp. 249-262 ◽  
Author(s):  
Z. Y. Tian ◽  
H. Vieker ◽  
P. Mountapmbeme Kouotou ◽  
A. Beyer
Keyword(s):  
Thermal Properties ◽  
Chemical Vapor ◽  
Functional Materials ◽  
Catalytic Performance ◽  
Structure Property ◽  
Temperature Oxidation ◽  
Spatially Resolved ◽  
Structure Property Relationships ◽  
Potential Applications

In situ emission and absorption FTIR methods were employed to characterize the spatially resolved structure of binary Co–Cu oxides for low-temperature oxidation of CO and propene. Co–Cu oxide catalysts were controllably synthesized by pulsed-spray evaporation chemical vapor deposition. XRD, FTIR, XPS, UV-vis and helium ion microscopy (HIM) were employed to characterize the as-prepared thin films in terms of structure, composition, optical and thermal properties as well as morphology. In situ emission FTIR spectroscopy indicates that Co3O4, CuCo2O4 and CuO are thermally stable at 650, 655 and 450 °C, respectively. The catalytic tests with absorption FTIR display that the involvement of Co–Cu oxides can initiate CO and C3H6 oxidation at lower temperatures. The results indicate that in situ emission and absorption FTIR are useful techniques to explore the thermal properties and catalytic performance of functional materials, allowing many potential applications in tailoring their temporally and spatially resolved structure-property relationships.

Real-time in situ rheology of alginate hydrogel photocrosslinking

Soft Matter ◽  
2011 ◽  
Vol 7 (24) ◽  
pp. 11510 ◽  
Author(s):  
Christopher A. Bonino ◽  
Julia E. Samorezov ◽  
Oju Jeon ◽  
Eben Alsberg ◽  
Saad A. Khan
Keyword(s):  
Real Time ◽  
Alginate Hydrogel

scholarly journals A tensile stage for high-stress low-strain fibre studies

2011 ◽  
Vol 44 (6) ◽  
pp. 1297-1299 ◽  
Author(s):  
Brian R. Pauw ◽  
Martin E. Vigild ◽  
Kell Mortensen ◽  
Jens W. Andreasen ◽  
Enno A. Klop
Keyword(s):  
High Performance ◽  
High Stress ◽  
Tensile Load ◽  
Structure Property ◽  
Structure Property Relationships ◽  
X Ray Scattering ◽  
Void Structure ◽  
Initial Results ◽  
Insight Into

Determining the effects of stress on the internal structure of high-performance fibres may provide insight into their structure–property relationships. The deformation of voids inside a poly(p-phenylene terephthalamide) (PPTA) fibre upon application of stress is one such effect which may be observed usingin situsmall-angle X-ray scattering. For this purpose, a compact in-vacuum stretching device is described here, capable of applying a force of up to 500 N using specially designed fibre clamps. Furthermore, a small radiative heater is placed around the fibre at the measurement position, so that the effects of the application of heat during tensile load can also be determined. Initial results show a slight but significant effect of stress and heating on the internal void structure of PPTA fibres. The effects on the void structure of heating and stress appear to be markedly different.

Designer Nanostructures Of Catalysts in the Environmental-HREM

1999 ◽  
Vol 5 (S2) ◽  
pp. 686-687
Author(s):  
Pratibha L. Gai
Keyword(s):  
Real Time ◽  
Selective Oxidation ◽  
Active Sites ◽  
High Resolution Electron Microscopy ◽  
Oxidation Catalysis ◽  
Atomic Scale ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Resolution Electron ◽  
Recent Developments

Major advances in the field of in situ environmental high resolution electron microscopy (EHREM) probe selective oxidation catalysis directly on the atomic scale. Dynamic gas-solid surface interactions are studied in real-time and under realistic reaction conditions to unravel atomic level insights into active sites and structure-property relationships in vital chemical and technological processes [1-3]. The recent developments include a pioneering approach with the controlled environmental cell (ECELL) facilities permanently mounted inside the EHREM [2]. Accessories have been added for simultaneous structural and compositional analyses of the reactor contents in real-time, and using atomic resolution imaging with transmission electron diffraction and parallel electron energy loss spectroscopy (PEELS). We are now developing innovative experimental methods that include very high temperature studies and combining in the same instrument facilities for both EHREM and environmental-SEM (ESEM), (EHREM-ESEM), with attractive possibilities for studying the science of selective oxidation catalysis.Alkane Catalysis, Chlorofluorocarbons and Nanotubes:In the domain of transition metal based oxides, discoveries of fundamental mechanisms underlying selective catalyzation have come from EHREM studies.

Polymorphism in Molecular Crystals

2020 ◽  
Author(s):  
Joel Bernstein
Keyword(s):  
Current Knowledge ◽  
Molecular Crystals ◽  
Crystal Form ◽  
High Energy ◽  
Structure Property ◽  
Energy Materials ◽  
Structure Property Relationships ◽  
System P ◽  
Protecting Intellectual Property

First recognized in 1822, polymorphism of crystals is now a widely recognized and observed phenomenon, with both fundamental and commercial ramifications in disciplines and industries that study and utilize solid forms of matter. The purpose of this edition is to summarize and to bring up to date the current knowledge and understanding of polymorphism in molecular crystals, and to concentrate it in one source. The information has been gleaned from a wide variety (~2500) of sources in the open literature; however, because of the increasing commercial importance of the phenomenon, a significant portion of the information is less accessible, we have attempted to include both the information from those sources as well with full details of their citations. An introductory chapter on fundamental concepts, definitions, and historical development is followed by a presentation of the physical and structural bases for crystallization and polymorphism. The exploration of the crystal form landscape is described in detail, including polymorph screens, concomitant polymorphs, and disappearing polymorphs. A survey of analytical methods for studying and characterizing polymorphs is followed by a discussion of rapidly developing computational methods for studying and attempting to predict polymorphic behavior. A chapter with many examples of the utilization of polymorphic systems to investigate structure–property relationships in solids precedes three individual chapters on the role and importance of polymorphism in pharmaceuticals, high energy materials, and pigments. The book closes with a chapter on the role of polymorphism in establishing and protecting intellectual property connected with polymorphs through the patent system.

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