Biodegradable thermoset shape‐memory polymer developed from poly(β‐amino ester) networks

Abstract

The purpose of this study was to develop a degradable thermoset shape-memory polymer from poly(b-amino ester) (PBAE) networks. PBAE was chosen to be the crosslinker as it is biodegradable and has been projected as a potential material for biomedical applications. The low glass transition temperature of PBAE was increased to a biomedically relevant range using methyl methacrylate and methyl acrylate as the linear chain builders. The thermo-mechanical properties of the networks were tailored such that they exhibited onset of glass transition temperature in between the room temperature (22 C) and the body temperature (37 C). Free-strain recovery tests under heating and isothermal conditions were performed to quantify shape-memory behavior. Testing showed that sampled programmed at 10 C ini-tiated deformation recovery at a lower temperature and a faster rate as compared to programming at 60 C. Higher thermal conductivity of water enabled the samples to recover faster in water than in air. Samples with higher PBAE crosslinking densities exhibited higher normalized mass loss under regular and accelerated conditions. The amount of water absorption in the networks also increased with the crosslinker concentration independent of the testing conditions.

A methodology for fabrication of thermomechanically activated switchable surface wettability

“…As the amount of 2HEMA is increased a fundamental point is reached at 75/25 wt % tBA:2HEMA where the character changes substantially, and the soaked and dry glass transitions diverge from each other. 40,42 A dramatic change in mechanical behavior over this transition region can also be seen in the stress-strain behavior shown in part (b). The Lakhera et al article agrees with this, and notes that at higher than 5% water absorption (close to 75/25 wt % tBA:2HEMA) mechanical tensile results also become much poorer.…”

“…[39][40][41][42] Similarly, a modifiable approach was also considered when choosing various surface treatments and application methods so that treatments could also be spatially varied on the pillared structure. The inherent benefit in the choice of these materials includes their proven shape memory characteristics when tailored correctly.…”

Semi-degradable poly(β-amino ester) networks with temporally controlled enhancement of mechanical properties

“…Due to the acrylate endgroups, in situ photopolymerization would be possible, which would allow for the delivery of drugs into complex spaces in vivo [5]. These polymer networks can also display shape-memory characteristics if their thermo-mechanical properties are tuned properly, allowing for their use as an implant material in minimally invasive procedures [46]. …”

An investigation on shape memory behaviors of epoxy resin system

“…Thermal-sensitive SMPs that use temperature change as their external stimulus are the most common SMPs. [1][2][3][4][5][6][7][8][9] Since the 1960s, covalently cross-linked polyethylene has found broad applications as heat-shrinking films or tubings. The importance of SMPs is gradually being taken seriously to date.…”