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Background: The Hip joint is the primary joint which gives stability to the human body. The wear and tear associated with age and other factors, require these joints to be replaced by implants using hip arthroplasty surgeries. Cobalt chromium alloy (CoCr), titanium alloy, stainless steel are some of the most common hip joint materials used for hip implants. The design requirement for hip joint implants are very stringent to avoid revision joint surgeries due to aseptic loosening. There are various choices in shapes and materials used for stem and acetabular designs. This makes it more difficult to make an informed decision on the type of design and material that can be used for hip implants., Methods: Circular, Oval, ellipse and trapezoidal designs with three individual cross sections (defined as profile 1, profile 2 and profile 3) are considered for the study. All models are modeled using CATIA V-6. Static structural analysis is performed using ANSYS R-19 to arrive at the best possible design and material combination for stem and acetabular cup., Results: It was found that, profile 2 of all the four designs has the lowest possible deformation and von Mises stress when compared to profile 1 and profile 2. In general, profile 2 with trapezoidal stem has best outcomes in terms of its mechanical properties. Besides, stem designed with material CoCr and its associated acetabular cup with CoC (ceramic on ceramic) material can produce an implant having better properties and longer durability., Conclusions: CoCr was found to be the preferred choice of material for stem design. It was also observed that, irrespective of material considered for the analysis profile 2 with trapezoidal stem showcased lesser deformation and von Mises stress over the other eleven models. For analysis involving acetabular cups, CoC implants exhibited better mechanical properties over the conventional CoPE (Ceramic on polyethylene) materials such as Ultra-high molecular weight polyethylene (UHMWPE). It is inferred from the findings of this study that, the profile 2 with trapezoidal stem design made of CoCr material and acetabular cup made of CoC material is best suited for hip joint implants.

Chitosan has gained an increased interest of researchers due to its nontoxic, biodegradable, biocompatible and renewable properties as well as its antimicrobial activity. In this work, a series of chitosan-based waterborne polyurethane (CS-WPU) emulsions were synthesized. The synthesis was accomplished by using a two-step emulsion polymerization process. The pre-polymer was prepared using hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG; MW = 6 kDa). Afterwards, the chain extension step was performed by using different mole ratios of chitosan. Moreover, the effect of chitosan on physicochemical properties of the emulsion was studied. To evaluate textile performances such as tear strength, tensile strength and pilling, the CS-WPU emulsion was applied on different plain weave polyester cotton dyed and printed fabrics by using pad-dry cure techniques. The antimicrobial activity of the treated and untreated fabrics was also evaluated via the agar diffusion method. The results displayed that incorporation of chitosan has prominent effects on tensile tear strength, tear strength and antimicrobial activity of polyester cotton dyed and printed fabrics. Moreover, antimicrobial activity was considerably enhanced as the mole ratio of the chitosan was increased. The results emphasize that CS-WPU based on HDI exhibits a better performance as compared to IPDI., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Polyurethane acrylate copolymers (PAC) were synthesized via emulsion polymerization following three step synthesis process using toluene-2,4-diisocyanate, hydroxy terminated poly(caprolactone) diol, 2-hydroxyethylacrylate (HEA) and butyl acrylate (BuA). Structural characteristics of the synthesized polyurethane acrylate copolymer (PAC) were studied using Fourier Transform Infrared (FT-IR) spectrophotometer and are with accordance with the proposed PAC structure. The physicochemical properties such as solid contents (%), tackiness, film appearance and emulsion stability were studied, discussed and co-related with other findings. The plain weave poly-cotton printed fabrics after application of PAC was evaluated applying colorfastness standard test method. The results revealed that emulsion stability is the main controlling factor of the synthesized material in order to get better applications and properties. The emulsion stability of the synthesized material increased with increase in molecular weight of the polycaprolactone diol., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Shape memory polyurethanes (SMPUs) were prepared from polycaprolactone diol 4000 (PCL 4000), 1,4-butanediol (BDO), chitin, dimethylol propionic acid (DMPA), triethylamine (TEA) and 4,4'-diphenylmethane diisocyanate (MDI), and the structures of the synthesized materials were verified by infrared spectroscopy. The effects of chitin and DMPA contents in the polyurethane formulation on surface properties were investigated. DMPA provides function of making hydrophilic polyurethanes. The crystalline structure of chitin enhanced the hydrophobicity of the synthesized materials. Contact angle, water absorption, surface free energy, work of water adhesion and swelling behavior of the synthesized polyurethanes were affected by varying the DMPA and chitin contents. The interactions of the PU films with solvents on the surface were clearly related to the contents of DMPA and chitin in the final polyurethane formulation.