scholarly journals Innovative Manufacturing Process of Functionalized PA2200 for Reduced Adhesion Properties

2020 ◽  
Vol 4 (2) ◽  
pp. 36
Author(s):  
Giovanna Rotella ◽  
Antonio Del Prete ◽  
Maurizio Muzzupappa ◽  
Domenico Umbrello

This work proposes an approach to fabricate micro patterned surfaces on PA2200 polyamide in order to improve its performance in terms of wettability and adhesion. In more detail, the present work aims to change the wettability of the surface and decrease their bacteria adhesion tendency. The experimental procedure consists of imprinting a set of different micro patterned structures over the polymer in order to verify the effectiveness of the methodology to change the contact angle of the surface, and in turn, reduce the occurrence of bacteria adhesion. Four different surface patterning were produced by laser ablation of a commercially pure titanium alloy, and then imprinted over the polyamide by surface stamping. The resulting surfaces were analyzed by topographical characterization and scanning electron microscopy. The wettability was probed by contact angle measurements while the bacteria adhesion was analyzed by adhesion test. The experimental results demonstrate the effectiveness of the method to modify the surface characteristics and to obtain a reliable patterned surface without using chemical hazardous material; opening to the possibility to replicate more complex structures and to obtain graded engineering surfaces.

Author(s):  
F Reshadi ◽  
S Khorasani ◽  
G Faraji

This study investigated the surface characteristics of ultrafine-grain commercially pure titanium (UFG CP-Ti) substrates produced by equal channel angular pressing (ECAP), compared with those of coarse-grain commercially pure titanium (CG CP-Ti) and Ti–6Al–4V (Ti-64) substrates. All Ti surfaces were sandblasted and acid-etched (SLA-treated) to produce micro-rough surfaces. Tensile and microhardness tests were carried out to measure the mechanical properties of fabricated samples. Then the surface characteristics of samples including contact angle measurements, surface morphology and in vitro cell response were evaluated after polishing, sandblasting and acid etching procedures. The results showed that after applying four passes of ECAP, the average grain size of microstructure decreased from 25 µm to 170 nm, while the ultimate tensile strength increased from 545 ± 24 MPa to 971 ± 38 MPa. Investigation of surface morphologies carried out by scanning electron microscopy indicated that ECAP-processed substrate exhibits nano-topography compared with CG CP-Ti and Ti-64 substrates after applying SLA process. In addition, the contact angle of SLA-treated CG CP-Ti and UFG CP-Ti substrates decreased from 68.3° to 9.5° and 51.9° to 7.4°, respectively, indicating a significant improvement of surface wettability. The morphologies of MG63 cells cultured on the developed surfaces proved the potential superior osteoblast cell compatibility of the micro-roughened surface made of UFG CP-Ti substrates over CG CP-Ti and Ti-64 substrates.


2011 ◽  
Vol 332-334 ◽  
pp. 209-212 ◽  
Author(s):  
Alireza Shakeri ◽  
Mehdi Joonobi

Kenaf nanofibers (NF) were isolated from the kenaf pulp using mechanical isolation methods (refining with super grounding and high pressure homogenization). The kenaf NF were acetylated to produce hydrophobic NF. FTIR results displayed a successful acetylation of the NF. X-ray analysis exhibited that the acetylation process reduced the crystallinity of kenaf NF but also that isolation to NF leads to higher crystallinity than corresponding micro-sized fibers. The contact angle measurements indicated that the acetylation treatment changed the surface characteristics of the kenaf NF from hydrophilic to more hydrophobic.


2015 ◽  
Vol 719-720 ◽  
pp. 29-37 ◽  
Author(s):  
Maral Rahimi ◽  
Peter Fojan ◽  
Leonid Gurevich ◽  
Alireza Afshari

Aluminium alloys are the predominant materials in modern industries. Increased knowledge about the surface characteristics of bare aluminium can enhance the understanding about how to optimize the working conditions for the equipment involving aluminium parts. This work focusses on the properties of native surface of aluminium alloy 8011, which is the main construction material for the production of air-to-air heat exchanger fins. In this study, we address its water wettability, surface roughness and frost formation in different psychometric parameters. The contact angle measurements revealed that this aluminium alloy exhibits a relatively high contact angle of about 78 degree, i.e. is not wetted completely. AFM measurements revealed significant surface roughness of typical heat exchanger fins. The thickness of formed frost was studied in relation to the wettability, humidity and the cold surface temperature.


2021 ◽  
Vol 24 (4) ◽  
Author(s):  
Gustavo dos Santos De Lucca ◽  
Anderson Daleffe ◽  
Gustavo Sebastião Scheffer ◽  
Marcio Afonso de Souza ◽  
Clauber Roberto Marques ◽  
...  

2021 ◽  
Vol 11 (3) ◽  
pp. 72-77
Author(s):  
Ivana Plazonić ◽  
Maja Rudolf ◽  
Valentina Radić Seleš ◽  
Irena Bates ◽  
Katja Petric Maretić

Surface characteristics of printing substrates are of the utmost importance to all types of paper that interact with ink. During all types of printing processes, the behaviour of the liquid phase (ink or dye) on the paper is directly defined by the paper cellulose-based surface. The printed ink spreads and penetrates more into paper fibres when the paper surface is rougher and more permeable. Contact angle measurements by sessile drop method are considered the most appropriate for determining the paper sheet surface energy. Paper as hydrophilic material has a high absorption rate resulting in a low contact angle. The objective of this study was to evaluate the surface free energy of laboratory-made papers containing straw pulp obtained from residues after the harvest of the most cultivated cereals in Croatia (wheat, barley and triticale). The obtained surface free energy results are promising for straw pulp usage in the manufacture of printing paper.


2012 ◽  
Author(s):  
Narjes Shojaikaveh ◽  
Cas Berentsen ◽  
Susanne Eva Johanne Rudolph-Floter ◽  
Karl Heinz Wolf ◽  
William Richard Rossen

2007 ◽  
Vol 330-332 ◽  
pp. 877-880 ◽  
Author(s):  
E.S. Thian ◽  
J. Huang ◽  
Serena Best ◽  
Zoe H. Barber ◽  
William Bonfield

Crystalline hydroxyapatite (HA) and 0.8 wt.% silicon-substituted HA (SiHA) thin films were produced using magnetron co-sputtering. These films were subjected to contact angle measurements and in vitro cell culture study using human osteoblast-like (HOB) cells. A wettability study showed that SiHA has a lower contact angle, and thus is more hydrophilic in nature, as compared to HA. Consequently, enhanced cell growth was observed on SiHA at all time-points. Furthermore, distinct and well-developed actin filaments could be seen within HOB cells on SiHA. Thus, this work demonstrated that the surface properties of the coating may be modified by the substitution of Si into the HA structure.


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