An official website of the United States government
Polymeric nanoparticles containing multiple amines and carboxylates have been frequently used in drug delivery research. Reproducible and controlled conjugation among these multifunctional biomaterials is necessary to achieve efficient drug delivery platforms. However, multiple functional groups increase the risk of unintended intramolecular/intermolecular reactions during conjugation. Herein, conjugation approaches and possible undesired reactions between multi-amine functionalized peptides, multi-carboxylate functionalized polymers, and anhydride-containing polymers [Poly(styrene-alt-maleic anhydride)-b-poly(styrene)] were investigated under different conjugation strategies (carbodiimide chemistry, anhydride ring-opening via nucleophilic addition elimination). Muti-amine peptides led to extensive crosslinking between polymers regardless of the conjugation chemistry. Results also indicate that conventional peptide quantification methods (i.e., o-phthalaldehyde assay, bicinchoninic acid assay) are unreliable. Gel permeation chromatography (GPC) provided more accurate qualitative and quantitative evidence for intermolecular crosslinking. Crosslinking densities were correlated with higher feed ratios of multifunctional peptides and carbodiimide coupling reagents. Selectively protected peptides (Lys-Alloc) exhibited no crosslinking and yielded peptide-polymer conjugates with controlled dispersity and molecular weight. Furthermore, anhydride ring-opening (ARO) nucleophilic addition elimination was successfully introduced as a facile yet robust peptide conjugation approach for cyclic anhydride-containing polymers.
more »
« less
Amination of polypropylene‐ g ‐(maleic anhydride) using reactive extrusion
Abstract We report synthesis of a radical scavenging aminated thermoplastic polymer through reactive extrusion of polyethyleneimine (PEI) with a polypropylene and polypropylene‐graft‐maleic anhydride (PP‐g‐MA) meltblend. The reaction was confirmed using acid orange 7 (AO7) amine density assay, toluidine blue O (TBO) carboxylic acid density assay, Fourier transform infrared spectroscopy (FTIR), and a migration assay. FTIR spectra revealed a reduction of the asymmetric stretching of the maleic anhydride (MA) carbonyl group at 1777 cm−1and the emergence of the maleimide carbonyl peak at 1702 cm−1. AO7 supported surface orientation of grafted amine groups by introduction of 7.22 nmol cm−2primary amines, corresponding to the reduction of surface carboxylic acids quantified by TBO from 12.46 nmol cm−2to 0.43 nmol cm−2. After incubation (40°C, 10 days) in ethanol, acetic acid, and water, < 0.1 mg cm−2PEI migrated from the materials, supporting the covalent nature of the grafting. Antioxidant activity was demonstrated exhibiting 5.90 and 4.31 nmol Troloxeqcm−2in aqueous and organic environments, respectively. Results indicate a successful condensation reaction during reactive extrusion, producing an aminated thermoplastic polymer with antioxidant activity for target applications such as food packaging, wastewater treatment, carbon capture, and others.
more »
« less
- Award ID(s):
- 1719875
- PAR ID:
- 10533788
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Applied Polymer Science
- ISSN:
- 0021-8995
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Post-polymerization modification (PPM) has been broadly employed to achieve functional polymer brush surfaces via immobilization of functional moieties on the brush using efficient organic tranformations. Here, we demonstrate the amine-anhydride reaction as a modular PPM route to functional brush surfaces using poly(styrene–maleic anhydride) (pSMA) copolymer brushes as a platform. The amine-anhydride reaction on pSMA surfaces proceeds to high conversions, with rapid kinetics, under ambient reaction conditions, and exploits a readily available library of functional amines. Using cystamine as a modifier, a convenient route to thiol-functionalized brushes was developed that enables sequential PPM modifications with a large library of alkenes using both base-catalyzed thiol-Michael and radical-mediated thiol–ene reactions. The high fidelity PPM reactions were demonstrated via the development of multifunctional, micropatterned brush surfaces.more » « less
-
Reported herein is a continuous one-step melt extrusion approach for highdensity polyethylene (HDPE) vitrimers. A grafting agent and a coagent were used to produce high-performing vitrimers. Maleic anhydride (MA) served as a reactive agent to facilitate crosslinking, while dimethyl maleate (DM) acted as a grafting enhancer by reducing the surface energy of HDPE grafted with MA. For comparison, MA alone was also tested as a grafting agent. The vitrimers obtained displayed superior mechanical properties compared with HDPE. The storage modulus, as well as crystallinity, were determined for the HDPE vitrimers. These vitrimers are reprocessable, thus supporting recycling efforts despite their crosslinked nature, owing to very fast relaxation due to low activation energy for the transesterification reaction. Consequently, these vitrimers are not only recyclable but also exhibit enhanced thermal and mechanical properties compared with conventional HDPE.more » « less
-
Abstract Reported herein is a continuous one‐step melt extrusion approach for high‐density polyethylene (HDPE) vitrimers. A grafting agent and a coagent were used to produce high‐performing vitrimers. Maleic anhydride (MA) served as a reactive agent to facilitate crosslinking, while dimethyl maleate (DM) acted as a grafting enhancer by reducing the surface energy of HDPE grafted with MA. For comparison, MA alone was also tested as a grafting agent. The vitrimers obtained displayed superior mechanical properties compared with HDPE. The storage modulus, as well as crystallinity, were determined for the HDPE vitrimers. These vitrimers are reprocessable, thus supporting recycling efforts despite their crosslinked nature, owing to very fast relaxation due to low activation energy for the transesterification reaction. Consequently, these vitrimers are not only recyclable but also exhibit enhanced thermal and mechanical properties compared with conventional HDPE.more » « less
-
Abstract Here, a reaction sequence that can be used to quantitatively modify the tyrosine residues in silk protein fromB. morisilkworms is demonstrated. A primary amine is installed ortho to the hydroxyl group on the tyrosine ring using a diazonium coupling reaction followed by reduction of the azo bond. The resulting amine is then acylated using carboxylic acid or NHS‐ester derivatives at room temperature and neutral pH conditions. The silk derivatives are characterized using1H NMR, UV–vis spectroscopy, ATR‐FTIR, and a unique method to follow this reaction sequence using isotopically labeled reagents and 2D NMR spectroscopy is also used. This study further demonstrates that this sequence can be used to install alkyne or azide functional groups which can undergo further bio‐orthogonal cycloaddition reactions under mild conditions. Finally, methods to carry out these modifications on solid silk microparticles and electrospun mats are also described.more » « less
