This series of publications describes research rendering soft polyisobutylene (PIB)‐based thermoplastic elastomers 3D printable by blending with rigid chemically compatible thermoplastics. The molecular structure, morphology, physical properties, and 3D printability of such blends have been systematically investigated. The authors' first report was concerned with the rendering of soft poly(styrene‐
Membranes are prepared by self‐assembly and casting of 5 and 13 wt% poly(styrene‐
- NSF-PAR ID:
- 10043259
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small
- Volume:
- 14
- Issue:
- 18
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract b ‐isobutylene‐b ‐styrene) (SIBS) 3D printable by blending with rigid polystyrene (PS). Here they report the macromolecular engineering of SIBS/polyphenylene oxide (PPO) blends for 3D printing. PPO, a rigid high‐performance thermoplastic, is compatible with the hard PS block in SIBS; however, neither PPO nor SIBS can be directly 3D printed. The microphase‐separated structures and physical properties of SIBS/PPO blends are systematically tuned by controlling blending ratios and molecular weights. Suitable composition ranges and desirable properties of SIBS/PPO blends for 3D printing are optimized. The morphology and properties of SIBS/PPO blends are characterized by an ensemble of techniques, including atomic force microscopy, small‐angle X‐ray scattering, and thermal and mechanical properties testing. The elucidation of processing‐structure‐property relationship of SIBS/PPO blends is essential for 3D printing and advanced manufacturing of high‐performance polymer systems. -
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ABSTRACT Sulfonated, block copolymers have traditionally been studied for applications in fuel cells and chemical protective clothing, among others. As such, most investigations have focused on the evaluation of transport properties and the selectivity and permeability of the polymer membranes. This work, however, focuses on the electrical characterization of sulfonated poly(styrene–isobutylene–styrene) (SIBS) triblock copolymer thin films. More specifically, the dielectric properties of SIBS are evaluated as a function of critical parameters such as frequency, sulfonation percent, and the polymer concentration. The results show that the dielectric constant increases with sulfonation percent and polymer concentration to values as high as 13,600. This work also provides insights into the correlation of SIBS electrical properties with its chemical structure and morphology. The structure–property relationship is derived through a combination of techniques including: elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and atomic force microscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.
2018 ,135 , 45662. -
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Abstract Block copolymers (BCPs) have received significant attention as promising candidates for sequestering nanoparticles and fabrication of aligned nanostructures with optimal optical or electrical properties. We investigate the influence of static and dynamic thermal field on the alignment of polystyrene‐
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T gof PS phase increase. In addition, the alkaline stability of the hPS/SEBS AEMs is also improved by addition of hPS. These findings suggest that the proposed method can develop high performance SEBS AEMs that are suitable for fuel cell applications. -
The separation of oil from water and filtration of aqueous solutions and dispersions are critical issues in the processing of waste and contaminated water treatment. Membrane-based technology has been proven as an effective method for the separation of oil from water. In this research, novel vertical nanopores membrane, via oriented cylindrical block copolymer (BCP) films, suitable for oil/water filtration has been designed, fabricated and tested. We used a ∼100 nm thick model poly(styrene- block -methymethacrylate) (PS- b -PMMA) BCP as the active top nanofiltration layer, processed using a roll-to-roll (R2R) method of cold zone annealing (CZA) to obtain vertical orientation, followed by ultraviolet (UV) irradiation selective etch of PMMA cylinders to form vertically oriented nanopores as a novel feature compared to meandering nanopores in other reported BCP systems. The cylindrical nanochannels are hydrophilic, and have a uniform pore size (∼23 nm), a narrow pore size distribution and a high nanopore density (∼420 per sq. micron). The bottom supporting layer is a conventional microporous polyethersulfone (PES) membrane. The created asymmetric membrane is demonstrated to be effective for oil/water extraction with a modestly high throughput rate comparable to other RO/NF membranes. The molecular weight dependent filtration of a water soluble polymer, PEO, demonstrates the broader applications of such membranes.more » « less
