Abstract Surface-analysis techniques including ISS, SIMS, XPS, and SEM are highly complementary and are essential for detailed investigations of rubber/metal bond failures. Multitechnique investigations offer the most effective means of solving problems in bonding applications. EDS, a near-surface analysis technique usually associated with SEM, is a versatile supporting technique for comprehensive studies. Contamination of materials used in bonding applications, especially by silicones, is a commonly encountered factor in bond failures. However, the extent and role of the contamination is often difficult to assess. Prepared test coupons exposed to silicone spray mist considered significant in this study exhibit isolated regions of silicone contamination that did not severely influence peel-test failure modes or maximum peel-load values. The techniques used in this study can be used independently or together to identify surface-treatment effects, determine failure locus, verify the presence of conversion coatings, primers, and adhesives, and identify contaminants in rubber/metal bonding studies. Failure characteristics of bonded assemblies vary and are often complex. Failure investigations of a high-performance mount that exhibits regions of apparent interfacial failure show silicone contamination is present in the failure regions. Intact regions of the same mount failed by fracturing in liquid nitrogen do not contain silicone and show a different failure locus. This suggests that only limited areas of the part were initially contaminated to the extent that bonding was affected; or the regions disbonded in service were exposed to silicone contamination after the failure was initiated.

Silicone rubber

Mist

10.5254/1.3538556

Cite

Citations (6)

Preparation of Nanocellulose-Based Biomaterials for Biomedical Applications

Proceedings of the International Conference of Theoretical and Applied Nanoscience and Nanotechnology (2023)

Zainab AlTamimi Saeed Tiari Xiaoxu Ji Davide Piovesan Allen R. Madura

Sustainable and eco-friendly biomaterials based on natural sources have increased dramatically, due to their recyclability, biodegradability, and biocompatibility.Cellulose is one of the most abundant natural biopolymers that can be produced from plants and microorganisms [1].Nanofibrillated cellulose (nanocellulose, NFC), the extracted form of the native cellulose, is composed of nanoscaled fibrils with a few micrometers in length and less than 100 nm in diameter [2].Owing to its biodegradability, biocompatibility, unique chemical binding capacity, and superior mechanical properties, NFC has attracted significant interest as an excellent alternative to petroleum-based polymer material for biomedical applications.In the current studies, we report the preparation of a biocompatible NFC-based surgery thread for dermal wound drug delivery application and the development of a low-cost and fully recyclable biocomposite for 3-D bioprinting manufacture, respectively.We prepared NFC surgery thread (nanothread) by extruding TEMPO-NFC (treated by 2,2,6,6-tetramethylpiperidine-1oxyl radical) hydrogel in an ethanol bath, followed by an air-drying process.Scanning electron microscopy (SEM) image showed that the as-fabricated nanothread has a mean diameter of ~120 µm and consists of well-aligned nanofibrils.The tensile strength test demonstrates the superior mechanical performance of the nanothread with a strength of 331 MPa and Young's modulus of 13.52 GPa, respectively.Due to its good water absorption capability, nanothread can absorb the physiological fluid and re-swell slowly.The capability to re-swelling provides an opportunity to release pre-loaded medicines in the nanothread, which can promote wound healing and prevent bacterial infection.We further incorporated fluorescent dye rhodamine 6G (R6G) to monitor the releasing profile.Our preliminary results showed that a non-linear releasing profile and the release of R6G can last for one week.The nanothread was loaded with gentamicin that showed very good antibacterial properties.Our previous studies showed that NFC based devices have good biocompatibility [3].We anticipate that the cell culture study will prove that the NFC thread can sustain cell growth as well and that the drug-loaded nanothread can be an effective strategy to promote skin wound healing.The abundant carboxylic groups and hydroxyl groups of the TEMPO-NFC nanofibril offer unique binding capacity with polysaccharides, proteins, surfactants, and plasticizers, which make the TEMPO-NFC an ideal adhesive material for 3-D bioprinting application [4].We are able to produce a novel low-cost, biodegradable and recyclable 3-D printing biocomposite that consists of NFC and brewer's spent grain (BSG).BSG is the major by-product waste from the brewing industry, consisting of 30% of non-cellulose polysaccharides [5].In a typical process, we blended NFC hydrogel with fine-grinded BSG particles.Our preliminary results show that the biocomposite is a sticky gel-like material and can further be stabilized by using glutaraldehyde, the rheology of which can be affected by BSG particle size and NFC ratio.A thermal stability test and tensile test will be conducted to evaluate the rheology and mechanical resistance.3-D printing of prototypes were demonstrated, including as an intelligent packaging indicator.We anticipate the biocomposite will be a low-cost, recyclable, and sustainable material that can be used for 3-D bioprinting manufacture.

Nanocellulose

10.11159/tann23.121

Cite

Citations (0)

A Sustainable Solution: Preparation of Nanocellulose Reinforced Brewer’s Spent Grain as a Fully Bio-Based 3D Printable Composite

Zainab Al Tamimi Longyan Chen Xiaoxu Ji Davide Piovesan Allen R. Madura

Abstract Brewer’s spent grain (BSG) is the largest waste generated from the brewing industry, accounting for ∼39 million tons yearly. Currently, the material has limited use for feeding farm animals and presents minimal market value. There has been a growing interest in the potential recycling of BSG as a manufacturing material. In this study, we are reporting the preparation of a fully bio-based 3D printable biocomposite based on recycled BSG material. The biocomposite is composed of BSG fine particles that are blended with nanofibrillated cellulose (NFC) hydrogel. Cross-linking agent glutaraldehyde was used to improve the viscosity of the biocomposite. Our results showed the composite is a paste-like material and adaptable for 3D printing. Scanning electron microscopy (SEM) and mechanical testing were used to evaluate the surface morphology and mechanical resistance of biocomposite, respectively. A prototype for food spoilage monitoring based on the BSG-NFC biocomposite was demonstrated. It is expected that this fully bio-based composite will be a low-cost, recyclable, and sustainable 3D bio-printing material for biological applications.

Nanocellulose

10.1115/imece2023-112780

Cite

Citations (0)

Use of Polymer Scaffolding and Electroplating to Create Porous Metal Structures

Journal of Engineering Materials and Technology (2019)

Adam Mihalko Jordan Felice Allen R. Madura Davide Piovesan

Additive manufacturing (AM) offers a fabrication process that provides numerous advantages when compared with traditional fabrication methods. Specifically, AM technology allows for the creation of porous media where porosity and permeability can be precisely controlled. When manufacturing metallic artifacts for biomedical use (e.g., bone implants), the investment in a laser sintering machine can be prohibitive for the budget-conscious enterprises limiting the study and use of this technology. Electroforming, electroplating, and electrotyping have been used for decades to replicate the complex shape of unique artifacts and can be viable techniques to create complex metallic shapes starting from a conductive mandrel. We investigated a fabrication technique that combines the stereolithographic additive manufacturing of a polymeric mandrel with electroforming, to obtain porous composites of polymers and metals. The fabrication method to electroform a porous artifact is presented, and an analytical model of the combined properties of the composite material is provided.

Mandrel

Electroforming

Selective laser sintering

10.1115/1.4042660

Cite

Citations (1)