Leoné, Nils; Roy, Manta; Saidi, Sarah; de Kort, Gijs; Hermida-Merino, Daniel; Wilsens, Carolus H. R. M.
Improving Processing, Crystallization, and Performance of Poly-l-lactide with an Amide-Based Organic Compound as Both Plasticizer and Nucleating Agent
In this work, we report on a novel hydrogen-bonding compound, N,N?-bis(2-hydroxyethyl)terephthalamide (BHET), and its potential as additive in poly-l-lactide (PLA). Although the hydroxyl groups of BHET can participate in transesterification with the PLA matrix, we demonstrate through gel permeation chromatography that extrusion at 200 °C does not result in a…
Effect of side chain and backbone length on lamellar spacing in polystyrene-block-poly(dimethyl siloxane) brush block copolymers
Fei, Huafeng; Yavitt, Benjamin M.; Kopanati, Gayathri; Watkins, James J.
We report the synthesis of polystyrene-block-poly(dimethyl siloxane) (PS-b-PDMS) brush block copolymers (BBCPs) through sequential ROMP of norbornene-modified macromonomers (-NB) and explore the effect of side chain length (Nsc) and total backbone degree of polymerization (Nbb) on the self-assembly of lamellar morphologies. Group I (PS-NB Mn = 2.9 kg/mol, PDMS-NB Mn…
Power Law Relaxations in Lamellae Forming Brush Block Copolymers with Asymmetric Molecular Shape
Yavitt, Benjamin M.; Fei, Hua-Feng; Kopanati, Gayathri N.; Winter, H. Henning; Watkins, James J.
We report the linear viscoelasticity of densely grafted poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) diblock bottlebrush block copolymers (dbBB) of equal mass fraction over a wide range of backbone degree of polymerization (Nbb = 21119). The difference in side chain length (PS Mn = 2.9 kg/mol, PEO Mn = 5 kg/mol) produces an…
Thermally Conductive and Electrically Insulating PVP/Boron Nitride Composite Films for Heat Spreader
Liu, Y.; Wang, N.; Ye, L.; Zehri, A.; Nylander, A.; Nkansah, A.; Lu, H.; Liu, J.
Thermally conductive materials with electrically insulating properties have been extensively investigated for thermal management of electronic devices. The combined properties of high thermal conductivity, structural stability, corrosion resistance and electric resistivity make hexagonal boron nitride (h-BN) a promising candidate for this purpose. Theoretical studies have revealed that h-BN has a
Liquid Crystal Elastomer Waveguide Actuators
Kuenstler, Alexa S.; Kim, Hyunki; Hayward, Ryan C.
While most photomechanical materials developed to date have relied on free-space illumination to drive actuation, this strategy fails when direct line-of-site access is precluded. In this study, waveguided light is harnessed by liquid crystal elastomer (LCE) nanocomposites to drive actuation. Using photo-chemical reduction of gold salts to plasmonic nanoparticles, prescription…
Protic Ionic Liquids Based on the Alkyl-Imidazolium Cation: Effect of the Alkyl Chain Length on Structure and Dynamics
Abdurrokhman, Iqbaal; Elamin, Khalid; Danyliv, Olesia; Hasani, Mohammad; Swenson, Jan; Martinelli, Anna
Protic ionic liquids are known to form extended hydrogen-bonded networks that can lead to properties different from those encountered in the aprotic analogous liquids, in particular with respect to the structure and transport behavior. In this context, the present paper focuses on a wide series of 1-alkyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquids,…
Effect of processing conditions on the mechanical properties of bio-inspired mechanical gradient nanocomposites
Zhang, Yefei; Edelbrock, Alexandra N.; Rowan, Stuart J.
Photo-induced thiol-ene crosslinking of allyl-functionalized cellulose nanocrystal (CNC)/polymer nanocomposites allows access to films that mimic the water-enhanced mechanical gradient characteristics of the squid beak. These films are prepared by mixing the functionalized CNCs and polymer in a solvent before solution casting and drying. The photocrosslinking agents are then imbibed into…
Nano-modified HDPE/PA6 microfibrillar composites: Effect of aminated graphite platelets coupling
Kelnar, Ivan; Bal, Ümitcan; Zhigunov, Alexander; Kaprálková, Ludmila; Fortelný, Ivan; Krej?íková, Sabina; Kredatusová, Jana; Dybal, Ji?í; Janata, Miroslav; Nofar, Mohammadreza
Modification of microfibrillar composites (MFCs) by nanofillers shows important effects of its localization on performance. This work deals with control of migration/localization of amine-modified graphite nanoplatelets (GNPAs) in the HDPE/PA6 system through their in situ coupling. GNPA/HDPE linking also leads to complex morphology of PA6 fibers. Although such control of…
Shape modulation of squaramide-based supramolecular polymer nanoparticles
Talens, Victorio Saez; Makurat, D. M. M.; Liu, Tingxian; Dai, Wei; Guibert, Clément; Noteborn, Willem E. M.; Voets, Ilja K.; Kieltyka, Roxanne E.
We report the synthesis and self-assembly of a library of squaramide-based bolaamphiphiles with variable hydrophobic and hydrophilic domain sizes, consisting of varied aliphatic chains (n = 2 to 12 methylene repeat units) and linear oligo(ethylene glycol) (m = 11 to 36 repeat units), to understand their effect on the formation…
Unraveling the high strain-rate dynamic stiffening in select model polyurethanes – the role of intermolecular hydrogen bonding
Wu, You-Chi Mason; Hu, Weiguo; Sun, Yuchen; Veysset, David; Kooi, Steven E.; Nelson, Keith A.; Swager, Timothy M.; Hsieh, Alex J.
This study elucidates the influence of molecular attributes on the observed dynamic stiffening in select two-component polyurethanes upon high strain-rate impact. Unlike typical segmented elastomers, polyurethanes consisting of poly(tetramethylene oxide), PTMO, and a diisocyanate, but without a chain extender, are investigated. The hexamethylenediisocyanate (HDI)-based polyurethane, HDI?PU,