Bulk, surface and blood-contacting properties of polyether polyurethanes modified with polydimetnylsiloxane macroglycols

Effect of intersegmental interactions on the morphology of segmented polyurethanes with mixed soft segments: A coarse-grained simulation study

Properties of extruded poly(tetramethylene oxide) Polyurethane block copolymers for blood-contacting applications

The physicochemical properties of an enhanced adsorbent material generated by clays and fungal biomass can be modified systematically. We used spectroscopic techniques to investigate the interaction mechanisms between biomass and clay and how surface properties change with synthesis temperature and clay amounts. Biomass-clay complexes were synthesized and either shock-frozen and freeze-dried or dried at 60 °C in the oven. Surface and bulk properties were analyzed by scanning electron microscopy, attenuated total reflectance-Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and by wettability and surface charge measurements. Interactions of specific biomass-related molecules with clay and changes in physicochemical properties were observed. Higher amounts of clay caused a decrease in particle aggregation while the biomass arranged more evenly. XPS proved interactions due to exchange reactions between Na from the clay and biomass external organic compounds. FTIR, wettability, surface charge, and XPS indicated a less ordered arrangement of the biomass on the clay when drying was performed at 60 °C. The properties of these types of materials define their potential use in future applications. These results indicate the possibility of the selective creation of bioclays: more hydrophobic, with a higher content of organic matter or more specific functional groups on the surface.

Waterborne polysiloxane–urethane–ureas (WBPSUU) were prepared through a prepolymer process using siloxane polyol, namely polydimethylsiloxane (PDMS) and polyether polyol, namely poly(tetramethyleneoxide glycol) (PTMG) as the soft segments. The goal of this study was to explore the potential use of polysiloxane–urethane–urea in marine coatings in order to boost the flexibility, adhesion, erosion, and foul-release property with respect to PDMS/PTMG ratio (PDMS wt%). The structural elucidation of the synthesized waterborne polyurethane and WBPSUU was carried out by FTIR, 1H NMR, and 29Si NMR spectroscopic techniques. The XPS and AFM analyses indicate that the polymer surface can be silicone enriched with the optimum PDMS content (15.76 wt%). The antifouling property of the coatings was investigated by the immersion test under a marine environment for 90 days. The fouled area was calculated for all the samples and the fouled area (%) decreased with increasing PDMS content. After 90 days the lowest fouled area (5%) was observed in the sample using WBPSUU4 (PDMS 15.76 wt%) among all of the samples.

This study investigates the use of industrial-grade polydimethylsiloxane (PDMS) for mass production of microfluidic chips through Liquid Silicone Rubber Injection Molding (LSR-IM) technologies. Injection molding of PDMS is ubiquitous in the automotive and aerospace industries. Yet, it is not currently applied to large-scale production of microfluidic devices. Here, we manufactured PDMS microfluidics devices using industrial IM systems and measured the values of several physicochemical properties of PDMS important in microfluidics. For the two grades of injection-moldable PDMS studied, properties were found close to those of the standard Sylgard 184 PDMS, except Young’s modulus, which varied from 66% to 250% of the Sylgard 184 value and the absorption of small molecules, which was lower or equal to that within Sylgard 184. Yet, the main benefits of LSR-IM production lie in its systematic process, resulting in an increase in reproducibility of both PDMS surface and bulk properties by decreasing the variance within and between production batches of several variables: Young’s modulus (30-fold), oxygen permeation (10-fold), mean fluorescence intensity of Nile Red (5-fold). Emphasis on biocompatibility of LSR-IM was evaluated by culturing complex and sensitive 3D biology models (tumor spheroids and explants) in injection-molded PDMS devices. We observed no significant differences in cell proliferation relative to samples cultured on conventional Sylgard 184 PDMS devices. Overall, these findings open a direct path from benchtop prototyping to industrialization of PDMS-based microfluidic devices for applications in healthcare.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-16863-z.

Novel polydimethylsiloxane (PDMS) based polyionenes were synthesized by a modified Menschutkin reaction involving reaction between bromo-terminated PDMS oligomers and various ditertiary amino compounds. In this study, the nature of the hard segment was varied by using various ditertiary amino compounds and in some cases by incorporating chain extenders, while the soft segment content was varied by changing the molecular weight of the PDMS oligomers. The mechanical properties of these materials were found to be dependent on both the nature and amount of the hard segments. These materials also showed distinct evidence of a microphase-separated morphology where under normal conditions, the hard segments formed in what are believed to be cylindrical ion-rich microdomains dispersed randomly in the soft PDMS matrix. When subjected to uniaxial deformation, the ionic cylinders were found to orient along their long axes in the stretch direction.

Event Abstract Back to Event Biomedical coatings prepared by magnetron sputtering Sandra Rodil1, Phaedra Silva-Bermudez2, Argelia Almaguer-Flores3 and Rene Olivares-Navarrete4 1 Universidad Nacional Autónoma de México, Instituto de Investigaciones en Materiales, Mexico 2 Instituto Nacional de Rehabilitación, Terapia Celular y Medicina Regenerativa, Mexico 3 Universidad Nacional Autónoma de México, Facultad de Odontología, Mexico 4 Virginia Commonwealth University, 2Department of Biomedical Engineering, United States Introduction: Nowadays, it is generally accepted that surfaces are critically important to determine the degree of tissue interaction between an implanted device and the host. Thus, much more importance has been given to study and modify the biomaterial surfaces to improve biocompatibility, cell adhesion, proliferation and differentiation. During the last years the research has evolved from the improvement of bulk properties and design of the implants to the development of a variety of bio-functional surface modifications, such as surface topography at both micro and nanoscale, adhesion of growth factors or coating deposition. The use of coatings allows the synthesis of hybrid materials, in which surface and bulk properties are de-coupled, so different functionalities (biocompatibility, antibacterial, etc...) could be obtained using the same substrate material. Materials: Metal oxide coatings (TiOx, ZrOx, TaOx and NbOx). Methods: The deposition of the coatings was done by reactive magnetron sputtering on stainless steel or titanium substrates. The coatings structure, composition and surface properties were measured. Electrochemical characterization using different electrolytes that simulate the biological fluids were used to evaluate the corrosion resistance provided by the coatings and the effect of the electrolyte composition on the response. The biological-surface interactions were also evaluated by studying protein-surface (adsorption), bacteria-surface (adhesion and biofilm formation) and cell-surface (adhesion, proliferation and differentiation) interactions. Discussion: The paper will presented a summary of the biological response from the four oxide coatings and the correlation between such response and the surface properties, including the effect of crystallinity or nanoroughness. One important factor to analyze is the fact that by using sputtered deposited coatings, it is possible to evaluate separately the effect of the surface chemical composition and the roughness, not so easily achieved when bulk materials are used. Conclusions: The in vitro results obtained from the different oxide coatings suggested that by using deposition methods, it is possible to create biomedical coatings that mimic the cellular response of the Ti-optimized metallic implants, with the advantage that such coatings could be deposited on hard-polymers or ceramics. UNAM PAPIIT Keywords: corrosion, Surface modification, surface property, Cell response Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Composites: polymeric, ceramic and metallic Citation: Rodil S, Silva-Bermudez P, Almaguer-Flores A and Olivares-Navarrete R (2016). Biomedical coatings prepared by magnetron sputtering. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01672 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sandra Rodil Phaedra Silva-Bermudez Argelia Almaguer-Flores Rene Olivares-Navarrete Google Sandra Rodil Phaedra Silva-Bermudez Argelia Almaguer-Flores Rene Olivares-Navarrete Google Scholar Sandra Rodil Phaedra Silva-Bermudez Argelia Almaguer-Flores Rene Olivares-Navarrete PubMed Sandra Rodil Phaedra Silva-Bermudez Argelia Almaguer-Flores Rene Olivares-Navarrete Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

ABSTRACTTwo series of polyester and polyether waterborne polyurethanes (WPUs) modified with poly[(3,3,3‐trifluoropropyl)methylsiloxane] (PTFPMS) were synthesized by prepolymerization method and the effect of PTFPMS on surface and bulk properties were investigated by a variety of experimental methods. FTIR and DSC results showed that the polyester WPU has better compatibility between soft segments and hard segments than polyether WPU in bulk and the degree of phase separation increased in polyester WPU but decreased in polyether WPU with increasing PTFPMS. ARXPS analysis revealed the migration of PTFPMS to WPU surface and the migration ability of Si element was better than F element. AFM images demonstrated that the surface of WPU films became rougher as PTFPMS content increased. The enrichment of PTFPMS with low surface energy and roughened surface imparted good hydrophobicity and oleophobicity to WPU films and polyether WPU has better surface properties compared with polyester WPU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46473.

The precipitation behaviors of intergranular carbides on various types of grain boundaries and their effect on tensile properties at room temperature were investigated systematically in Inconel 690 tubes. Precipitates of intergranular chromium carbide were identified as Cr-rich M23C6. It was observed that the M23C6 carbide behavior is obviously influenced by grain boundary character and interfacial energy. The intergranular M23C6 carbides were suppressed on low-angle boundaries and coincidence-site lattice boundaries. Plenty of M23C6 carbides precipitated at random high-angle boundaries with high interfacial energy. With increasing aging time, the precipitated carbides became coarse and grew into the matrix near grain boundaries. The ultimate tensile strength and elongation of the Inconel 690 tube solution annealed at 1373 K (1100 °C) for 15 minutes were 671.2 MPa and 47.2 pct, respectively. After aging treatment, the ultimate tensile strength and elongation drastically decreased with increasing aging time. The tensile test generated a number of cracks at the grain boundaries due to coarse intergranular M23C6 carbides near the fracture. Both the decrease of ultimate tensile strength and elongation of the aged Inconel 690 tube were mainly caused by breaking of the coarse M23C6 carbide and reduced chromium concentration in the matrix.

Many industrial processes involve the modification of surfaces. The semiconductor and microelectronics industries are extremely reliant upon surface processing [1], but other applications include solar cells, MEMS and microfluidics, thermal barrier coatings, and fuel cells. Optical measurements are commonly used to indirectly quantify the surface and bulk properties of materials. Unlike direct imaging methods, in which the local surface topography is visualized, indirect methods provide information on surface and bulk properties which are averaged over the entire area being sampled. Typically, a beam of light is directed at the surface to be measured, and the light interacts with the surface to produce the reflected or diffracted light that is then measured by a photodetector. One advantage of indirect measurement techniques is that they are non-invasive, and therefore can be used in extreme or harsh processing environments such as vacuum chambers and reaction vessels by passing the light through windows. These in situ optical sensors have been used for process control of film thickness and chemical composition. However, many more microscopic and nanoscale surface properties can be measured and potentially controlled using optical sensors. The barriers include the difficulty of modeling the optical response, the difficulty of inverting these relationships to robustly infer surface properties, and the practicality of including windows on the chamber to enable optical access. However, to create precise nanostructures in a high-throughput manufacturing setting, real-time measurement and control will be required, and optical sensors are expected to play a significant role.

Polyamideimide (PAI)–epoxysilane (coupling agent) composites were reacted with oligomeric polydimethylsiloxane (PDMS), a condensation product of difunctional silane, by using the sol–gel process, and were then dried into films. After this procedure, the surface, mechanical, and thermal properties were measured. The study showed that PDMS existed in the PAI matrix by the use of FTIR. With respect to mechanical properties, the maximum elongation and toughness were increased in the PAI with silane groups, although the maximum tensile strength was slightly decreased. In this experiment, PAI–30 wt % epoxysilane composite had the best mechanical properties. The intensive dispersion of the silane groups on the surface of PAI was confirmed through XPS measurement. As a function of the siloxane contents, the TGA curve shows less thermal stability in terms of their initial weight loss. However, in an oxygen atmosphere at about 700°C, the series of PAI–siloxane composites indicated a significant increase in char concentration. In the end, PAI with a relevant amount of silane groups was improved in both toughness and surface properties. This experiment showed that PDMS added to PAI had better properties than those of classical materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1774–1783, 2004

The current study examines various filter configurations, argon bubbling, and degasser addition to improve melt cleanliness of AZ91E permanent mold castings. The unfiltered castings had an average yield strength, ultimate tensile strength, and elongation of 93.3, 153.3 MPa, and 2.2% respectively. Using a fine mesh filter within the well of the mold, the ultimate tensile strength and elongation increased by 9 and 41%, respectively, compared to the unfiltered samples. A combination of a fine filter and argon bubbling resulted in an average increase in ultimate tensile strength and elongation of 29 and 123%, respectively, that matched the performance of the C2Cl6-based degassed castings with 95.8, 194.3, and 4.9% for yield strength, ultimate tensile strength, and elongation, respectively. The addition of the C2Cl6-based degasser released harmful vapors that can be avoided using the fine filter with argon bubbling. In all cases, the removal of MgO-based inclusions improved mechanical properties.

Thickness effect on the mechanical behavior of PLA specimens fabricated via Fused Deposition Modeling

To better investigate the degradation and biocompatibility of waterborne biodegradable polyurethanes for tissue engineering, a series of new waterborne biodegradable polyurethanes (PEGPUs) with low degree of crosslinking was synthesized using IPDI, BDO and L-lysine as hard segments, PCL and PEG as soft segment. The bulk structures and properties of the prepared polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile mechanical tests and water contact angle (WCA) measurements. The degree of microphase separation was slightly improved because of the lowered crosslinking degree of these PEGPUs in comparison with the high cross-linking degree samples, leading to good mechanical properties, as indicated by DSC and stress-strain data. Moreover, biodegradability of the polyurethanes was evaluated in phosphate buffer solutions (PBS) under different pH values and enzymatic solution at pH 7.4 through weight loss monitoring. The results suggested that the degradation of these PEGPUs was closely related to their bulk and surface properties. And the degradation products didn’t show apparent inhibition effect against fibroblasts in vitro. These studies demonstrated that the waterborne biodegradable polyurethanes could find potential use in soft tissue engineering and tissue regeneration.

The purposes of the studies are to investigate the phase transformations, mechanical properties and microstructures of Fe-5Cr-4.5Ni-2Mo-0.5Ti-0.3Al-0.2C alloy by use of X-ray diffraction (XRD), optical microscope (OM) and transmission electron microscope (TEM). Some results are described as following: Being SHT, the ultimate tensile strength, yielding strength and elongation of the alloy are in the range of 965-1380 MPa, 930-1260 MPa, 6.5-3.8 %, respectively. After aged at 450-650 ℃ for various times, the ultimate tensile strength, yielding strength and elongation of the alloy are in the range of 1180-1690 MPa, 1040-1520 MPa, 17.0-8.2 %, respectively. Being solution heated treatment at 1100℃/1 H, the microstructure of the alloy is a plate martenite phase belonging to the B.C.C. structure. In addition, some TiC carbides were found within the matrix. When aged at 450 ℃ for various times, some α-phase precipitates had been found. And, increasing the aging temperature to 550℃, it can be observed that the L12 -type precipitates formed within the matrix. Age 650-750 ℃ for various times, the M23C6-type carbides and austenite phase formed.