Papers by Keyword: Polymeric

Abstract: The paper presents the development of a scientific cloud computing community for polymeric and composites products that offers high performance computation capability. The scientific research community will use the cloud to resolve complex issues. This community will include data storage, a polymeric materials encyclopaedia, softwares for simulation, design, so will determine a functional independence. Cloud computing will increase the productivity and innovation in all polymeric and composites field. The software platform consists of several virtual machines running a Unix (or derivatives as Linux or *BSD’s) operating systems using specialised software, Open Source software for materials and process modeling, a scientific package for polymeric material simulations.

Abstract: A novel flame retardant additive, DOPO-based polymeric phosphate (PFR-D), which simultaneously contained phosphorus and sulfur, was synthesized from 9,10-dihyro-9-oxa-10-phosphaphnanthrene-10-oxide (DOPO), POCl₃ and bisphenol S. And the structure of PFR-D has been characterized by ¹H-NMR, ³¹P-NMR and FT-IR. PFR-D was used as additive in polycarbonate/acrylonitrile-butadiene-styrene alloy (PC/ABS). The UL94 V-0 rating was achieved by addition of 5-7% PFR-D in PC/ABS, the LOI reached 27.5%. The thermal degradation of PFR-D and polymers with it was investigated by TGA, and the results showed that addition of PFR-D apparently changed the pyrolysis pathways of PC/ABS. The TGA curves indicated that the flame retardant effect was attributed to promoting the char yield by involving the polymer in charring.

Abstract: A novel polymeric phosphate flame retardant (PFR-P) was synthesized from 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphbicyclo [2.2.octane (pentaerythritol phosphate, PEPA), POCl₃ and bisphenol S. Phosphorus was bonded both in the main chain and in the pendant group of flame-retardant polymer molecule, reached a content of 13.1%. And sulfur content was 6.75%. The thermal stability was investigated by TGA, and the results showed that the initiative decomposition temperature was 334°C with 41.1% charring residue at 500°C under air. The high phosphorus and sulfur content contributes an excellent flame retardancy to PC/ABS without a considerable decrease of mechanical properties. It is a potential flame retardant for other polymer systems.

Abstract: In this paper, design, simulation and optimization of a novel electrothermally-activated polymeric microactuator capable of generating combination of bidirectional lateral and rotational motions are presented. The composite structure of this actuator is consisted of a symmetric meandered shape silicon skeleton, a SU8 thermal expandable polymer and a thin film chrome layer heater. This actuator is controlled by applying appropriate voltages on its four terminals. With the purpose of dimension optimization, a numerical parametric study is executed. The modeled actuator which is 1560 μm long, 156 μm wide and 30 μm thick, demonstrates a remarkable lateral displacement of 23 μm at power consumption of 38 mW and a considerable rotation of about 7.5° at the same power consumption but with excitation of different terminals.

Abstract: Since the Medical Device Amendments of 1976 were enacted, the FDA considers Tissue Adhesives as “Transitional Devices” that are classified as Class III medical devices and are marketed in the United States subsequent to the approval of a Pre-market Approval Application (PMA). On February 9, 2006, Regulatory & Clinical Research Institute, Inc. submitted a petition to FDA to reclassify tissue adhesive transitional medical devices for skin approximation from Class III to Class II (special controls). FDA consulted with the General and Plastic Surgery Devices Advisory Panel, and on August 25, 2006, in a public meeting, the panel unanimously recommended that the tissue adhesive transitional medical devices for topical approximation of skin be classified from class III into Class II. Consequently, since June 30, 2008, following the effective date of the FDA Final Rule [1] that reclassified tissue adhesive transitional medical devices for skin approximation, any firm submitting a Premarket Notification [510(k)] for a tissue adhesive for the topical approximation of skin will need to address the issues covered in the published “Class II Special Control Guidance Document: Tissue Adhesive for the Topical Approximation of Skin, dated May 30, 2008” [2]. Accordingly, the firm needs to show that its device meets the recommendations of the published Class II guidance document or in some other way provides equivalent assurances of safety and effectiveness. Also, the author provides a short regulatory description of US FDA, under what laws its operates, how FDA evaluates new medical devices for marketing as Class I, Class II, and Class III [3].

Abstract: In this work, we present the characterisation of an electrothermally actuated microgripper that operates in both dry and liquid media, and shows improved performance versus existing devices. The microgripper, fabricated in a combination of polymeric (SU8) and conductive materials (Au), is able to produce displacements up to 110 μm in air and 30 μm in liquid. In both cases, the voltage and the electrical power required is minimal (less than 3 V and 180 mW respectively) and so both, high temperatures and electrolysis, are prevented. Micromanipulation experiments have successfully demonstrated the gripping, holding and transport of mice oocytes (approx. diameter 100 μm) in a biological media.

Abstract: A brief description of the uses and clinical applications of synthetic cyanoacrylate polymer adhesive/glues that have been cleared and/or approved as medical devices by FDA since the Medical Device Amendments of 1976 were enacted. This includes cyanoacrylate Class I devices (Exempt and not Exempt devices), Class II cyanoacrylate devices such as Dental Cements and Orthodontic Bracket Adhesives, and Class III (PMA) devices such as Dermabond™, Indermil™ Tissue Adhesive, and Trufill® n-Butyl Cyanoacrylate Embolic Agent. By citing an example of recently FDA approved Class III (PMA) devices in the Cyanoacrylate technology, the author provides a brief discussion of the FDA approval process of medical devices. It includes the FDA issues regarding the published guidance document for "Cyanoacrylate Topical Tissue Adhesives" that will provide guidance to regulatory personnel and manufacturers in the preparation of IDE applications and in the development of valid scientific evidence to support PMA applications for cyanocrylate tissue adhesives intended for topical approximation of skin and others. Also, the author provides a short regulatory description of US FDA; under what laws its operates, how FDA evaluates new devices for marketing, and how the device regulatory system works, for example, Class I, Class II, and Class III cyanoacrylate medical devices.