Biomedical Polymers Processing

Techniques commonly used in processing biomedical polymers fall into two categories thermal and solvent borne. In thermal processing, the polymer is heated above its glass transition temperature (Tg) or the melting point (T ) to make the polymer flow. The softened or the molten polymer is forced through a die or into a cold mold under pressure, cooled rapidly to form the solid-product with desired size and shape [3]. The process can be either continuous or semi-continuous. 

Damodaran et aL, Biomedical Polymers, SpringtaBriefs in Applied Sciences and Technology, DOI 10.1007/978-3-319-32053-3 3 

Thennal processing Extmsion Rods, films, filaments and fibers 

Solid free form fabrication (SFF) Fusion deposition modeling 3D printed parts 

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Rosato, D. V., Polymers. Processes and Properties of Medical Plastics in Synthetic Biomedical Polymers, Szycher-Robinson (eds.), Technomics, 1980. 

Chemical engineers are actively involved in developing improved polymer processing and devices relevant to biomedical engineering. Another important research area is the physical and biological treatment of hazardous wastes. Computational methods are now used extensively in modeling studies, and computer simulation is routinely employed in plant design. 

Sn(II) 2-ethylhexanoate, which has been approved for surgical and pharmacological applications by the FDA, is generally employed as the catalyst for the synthesis of biomedical polymers. However, it has been reported that Sn(II) 2-ethylhexanoate cannot be removed by a purification process such as the dissolution/precipitation method, thus the residual Sn may be concentrated within matrix remnants after hydrolytic degradation (2). To avoid the potential harmful effects of metallic residues in biomedical polymer materials, enzymatic polymerization is one of the powerful candidates for polymer synthesis (3). Enzymes, natural kinds of protein without toxicity, have remarkable properties... 

The chemical engineer will be interested particularly in applying the basic principles of transport phenomena to problems involving separations processes, combustion, polymer processing, interfacial hydrodynamics, multiphase flow, and biomedical engineering. In all of these areas it will be the task of the chemical engineer to utilize the basic theory of transport phenomena innovatively in solving practical problems for the beneflt of society. 

Requirements for biomedical pxslymer production and processing besides the strict control on biomedical polymer itself, matters harmful to human body shall also be prevented during material pa-oduction the purity of the raw materials used in biomedical polymer synthesis shall be strictly controlled, no harmful matter is allowed and the content of heavy mental shall be within the limit additive processing shall meet medical standard the production environment should meet proper standard for cleanliness. 

FTIR is another surface-sensitive spectroscopic tool to analyze biomedical polymers since sample preparation is very simple for this technique. FTIR spectra should be recorded in reflection mode instead of transmission mode in order to analyze the functional groups present on polymer surfaces. ATR-FTIR has been apphed to study in vitro mineralization of porous starch scaffolds cultured in bone marrow stromal cells harvested from Wistar rats. Mineral deposition in in vitro cultures is usually followed by von Kossa stain or Alizarin red stain or by calcium uptake. These methods provide erroneous results because the scaffold matrix itself can take up some calcium from the medium. ATR-FTIR is devoid of the limitation and provides reliable information on the mineralization process. In the... 

The use of polymers in medicine is steadily growing. The synthetic and processing flexibility of polymers continue to permit polymers to be applied in a broad range of medical, biological, and implant applications. Creative polymer synthesis continues to expand the functionality and tunability of polymers for medical applications. There are now excellent biomedical polymers available to address general needs in medidne (the subject of this chapter). Opportunities that present themselves for enhanced or improved biomedical polymers are in the following areas ... 

The zeta potential (Q is thought to be the same as the Stem potential which is defined at the plane dividing the Stem layer and the diffuse layer of the EDL. Zeta potential is an experimentally measurable electrical potential that characterizes the EDL, and it plays an important role in many apphcations such as stability of colloidal dispersion, characterization of biomedical polymers, electrokinetic transport of particles, and capillary electrophoresis, etc. In addition, zeta potentials of the particles and the channel wall are cmcial to the design and process control of microfluidic devices. A review on measuring the zeta potential of microfluidic substrates was provided by Kirby and Hasselbrink [3]. 

In this chapter, we discuss various synthetic strategies commonly used for preparing synthetic biomedical polymers by classifying them on the basis of the type of polymerization. A brief mechanistic description of each type of synfliesis is illustrated with representative examples to provide a better understanding of the process and polymers prepared by the technique. 

Table 3.1 Common techniques for processing biomedical polymers...

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