Rheological characterization of carbon black/varnish suspensions

Author(s):  
Yuji Aoki
2009 ◽  
Vol 66 ◽  
pp. 139-142 ◽  
Author(s):  
Ji Jun Qian ◽  
Ai Ping Chen ◽  
Zhong Xin Liu ◽  
Chun Zhong Li

The rheological properties of carbon black gel ink were investigated by measurement the relationship between shear stress and shear rate. The fitting to the common rheological curve of gel ink with Hersegel-Bulkley equation was introduced. And the rheological parameters used to characterize the writing properties of gel ink were proposed. The results indicated that the gel ink system possessed strong shear-thinning ability. And the writing performance of the gel ink could be characterized with rheological parameters comprehensively.


2001 ◽  
Vol 74 (5) ◽  
pp. 899-914
Author(s):  
A. Limper ◽  
D. Schramm

Abstract In comparison to plastics processing, rubber processors handle a much more complex material. Due to active fillers used in rubber compounds, such as carbon black and silica, in some cases extraordinary filler/filler interactions occur. In general the multi-component system leads to a very complex rheological behavior. If silica compounds e.g. are processed the chemical modification of the filler surface (by organosilanes) has to be taken into account. By this the rheological behavior of the material changes dramatically. All these circumstances make rubber processing to a very complex theme. This paper presents results which are obtained within an European research project. The work is focussing on a better process description of the extrusion process of rubber compounds. It handles both applications of the extrusion process, i. e. for technical rubber goods or for making tire parts like the extrusion of tread stripes. Hence in this paper a new approach for modeling the flow in the extruder screw will be presented. Using this as a simulation tool a systematic analysis of the extrusion process is possible in reasonable time. Another field of interest in this context is the rheological characterization of rubber compounds with a so called „Extrusion-Rheometer“. The advantages of this device will be shown for the investigation of processability and gathering representative rheological data for recalculations of screw and die flow in the extrusion process.


TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.


Author(s):  
Luiz Eduardo Rodrigues Vieira ◽  
Leonardo Rosa Ribeiro da Silva ◽  
Felipe Chagas Rodrigues de Souza ◽  
Wisley Sales ◽  
Álisson Rocha Machado

Author(s):  
Joel López Bonilla ◽  
Cesar Celis ◽  
Danmer Maza

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 948
Author(s):  
Nicola Zerbinati ◽  
Sabrina Sommatis ◽  
Cristina Maccario ◽  
Maria Chiara Capillo ◽  
Giulia Grimaldi ◽  
...  

(1) Background: Injectable hyaluronic acid (HA) dermal fillers are used to restore volume, hydration and skin tone in aesthetic medicine. HA fillers differ from each other due to their cross-linking technologies, with the aim to increase mechanical and biological activities. One of the most recent and promising cross-linkers is polyethylene glycol diglycidyl ether (PEGDE), used by the company Matex Lab S.p.A., (Brindisi, Italy) to create the HA dermal filler PEGDE family. Over the last few years, several studies have been performed to investigate the biocompatibility and biodegradability of these formulations, but little information is available regarding their matrix structure, rheological and physicochemical properties related to their cross-linking technologies, the HA content or the degree of cross-linking. (2) Methods: Seven different injectable HA hydrogels were subjected to optical microscopic examination, cohesivity evaluation and rheological characterization in order to investigate their behavior. (3) Results: The analyzed cross-linked dermal fillers showed a fibrous “spiderweb-like” matrix structure, with each medical device presenting different and peculiar rheological features. Except for HA non cross-linked hydrogel 18 mg/mL, all showed an elastic and cohesive profile. (4) Conclusions: The comparative analysis with other literature works makes a preliminary characterization of these injectable medical devices possible.


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