Sharif Digital Repository

Shape Memory Polymers (SMPs) are a class of smart materials capable of remembering multiple shapes, and transitioning between them in response to an external stimulus such as thermal or magnetic induction. SMPs have attracted significant attention of both industrial and academic researchers due to their useful and attractive functionality. This thesis aims to analytically develop Euler-Bernoulli, Timoshenko and von Karman theories for beam bending in small strain regime considering SMP constitutive equations. To properly introduce analytical solution for the problem of beam bending, the constitutive model proposed by Baghani et al. (2012) has been used. For this purpose, three dimensional... 

Smart bio-based shape memory polymers with high performance and fast response have the exciting potential to meet the growing need in biomedical applications. A fascinating approach in SMP categories in biomedical field is the development of noncontact activation without increasing the environmental temperature through remote triggering methods, such as magnetic triggering. Magnetically responsive SMPs have received lots of attention in the biomedical applications, especially the non-contact triggering of medical equipment and implants inside the body. In this study, the biocompatible nanocomposite based on shape memory polyurethane acrylates (SMPUAs)/ hybrid carbon-magnetic nanoparticles,... 

Shape memory polymers (SMPs) are a class of multi-phase smart materials that have the ability to return from a deformed to their original shape . The origin of SMP material features is a reversible glassy-rubbery phase transformation between a high stiffness glassy phase and a low stiffness rubbery phase . Thus , according to experimental observations , the phase transformation must be considered in the constitutive model development . In most applications , SMPs experience arbitrary thermo-mechanical loadings . Moreover , SMP structures typically undergo large rotations and strains and the use of a finite deformation scheme is preferred. In this thesis , we study the SMP behavior under... 

Semi-crystalline polylactic acid (PLA) and amorphous polymethyl methacrylate can form a soluble and miscible alloy in which the crystalline regions in the polylactic acid act as the fixed and immutable region and amorphous regions of the two polymers act as the changeable region. The two polymers can form a lattice structure with physical connections having shape-memory. So that the deformed polymer returns to its original shape above a certain temperature. These materials are used in sensors, smart materials, and medicine. On the other hand, Polyethylene glycol (PEG) is compatible with polylactic acid (PLA) and it seems that adding it will increase the ductility of polylactic acid (PLA). In... 

Shape memory polymers have the potential to use in the field of biomedical applications. In this research, polyurethane structures have been synthesized based on the Diol mixtures, consisting of polycaprolactane diol (PCL-diol) and poly (lactic acid) diol (PLA-diol). Aim of reasearch is about evaluating poly (lactic acid) effect in structure of the polyurethane. At the same time, cellulose nanocrystals (CNC) have been added to polymer matrix to improve properties. The synthesis of acrylated polyurethane, included the synthesis of polyurethane acrylate prepolymer. Next, this prepolymer has been cured by adding the reactive diluent and some polyol. The cured systems were investigated, finally,... 

The current research focuses on preparing conductive hydrogels with combined shape memory and actuating under the effect of external stimuli. Two studies were conducted in which hydrogels simultaneously showed shape memory and actuating behaviors. The magnetic carrageenan-based double network hydrogels were prepared in the first part. The presence of magnetic nanoparticles not only strengthened the mechanical properties, but also induced shape memory properties under a magnetic field. These hydrogels had good electrical conductivity and showed successful performance as strain sensors. The hydrogels performed well in simple and complex shape memory experiments in response to the temperature....