Abstract
Dog-bone shaped poly(methyl methacrylate) (PMMA) samples were pre-stretched at different temperatures (within the glass transition range and slightly above) to different strains. Subsequently, these pre-stretched samples were aged at 40 °C for up to three months, and finally, all samples were uniaxially stretched to fracture. The Young’s modulus, ultimate stress and toughness of the samples were obtained and plotted as a function of the temperature, and strain in pre-stretching in the contour format. The influence of aging was revealed when the contours of different aging times were compared. One of the most interesting findings was that the toughness of this PMMA can be tailored via controlling the temperature and strain in pre-stretching. The toughness of the pre-stretched samples ranged from 1.317 MJ/m3 to 23.281 MJ/m3 (without aging) and from 1.476 MJ/m3 to 27.532 MJ/m3 (after three months of aging). Based on the results of a series of additional experiments, a mechanism was proposed to reveal the fundaments behind the influence of the temperature and strain in pre-stretching and aging.
Highlights
It is possible to modify poly(methyl methacrylate) (PMMA) to form crystalline structures as recently reported in [1], commercial PMMA is mostly amorphous
As amorphous PMMA has been confirmed to be an excellent shape memory polymer (SMP), in this study, we investigate the influence of stretching temperature, stretching strain and aging on the Young’s modulus, ultimate stress and toughness of the programmed/pre-stretched PMMA samples
It appears that the significance of this “melting” transition in the second heating process highly depends on the highest temperature in the previous heating process
Summary
It is possible to modify poly(methyl methacrylate) (PMMA) to form crystalline structures as recently reported in [1], commercial PMMA is mostly amorphous. For the heating-responsive SME in polymers based on the glass transition, the standard process of a full shape memory cycle includes two steps. As reported in [28], after aging at 40 ◦C for up to one year, the PMMA samples programmed via high temperature (within the glass transition range and slightly above) uniaxial stretching to up to 80% strain are still able to almost fully recover their original shape upon heating. As amorphous PMMA has been confirmed to be an excellent shape memory polymer (SMP), in this study, we investigate the influence of stretching temperature (programming temperature), stretching strain (programming strain) and aging (at 40 ◦C for up to three months) on the Young’s modulus, ultimate stress (the maximum engineering stress until fracture) and toughness of the programmed/pre-stretched PMMA samples. Smaller sized samples (about 10 mg) were prepared for differential scanning calorimetry (DSC) tests
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
