Self-Activation of Poly(methylenelactide) through Neighboring-Group Effects: A Sophisticated Type of Reactive Polymer

The present work reports on a reinvestigation of a radical polymerizable lactide derivative since the polymerization properties were only poorly studied in the first publication in 1969. The optically active methylenelactide was polymerized by free radical polymerization in solution using AIBN as an initiator and resulted in isotactic-biased atactic optically active poly­(methylenelactide) according to ¹H NMR and ¹³C NMR spectroscopies and specific rotation angle measurements [α]²⁰_D = −38.5 ± 0.5°. The molecular weights range between 4 × 10⁴ and 1 × 10⁵ g mol^–1 with dispersities of ca. <i>D</i> = 2.5 and a detected glass transition temperature of 244 °C. IR spectra of the polymers indicate different ester reactivities (ν_a = 1779 cm^–1, ν_b = 1755 cm^–1) that can be referred to as neighboring-group effects. These highly activated esters react readily with nucleophiles in polymer analogous reactions. Thus, the aminolysis of poly­(methylenelactide) was performed under mild conditions with varied amines. In the case of aminolysis with tetrahydrofurfurylamine, a nonstable cloud point in water was observed

One-Step Approach to Amino-Functionalized Semiaromatic Polyamides: Modification and Cross-Linking

The new method for the one-step synthesis of semiaromatic polyamides bearing primary aromatic amine groups in the repeating units is presented. Various aliphatic and aromatic diamines were used: 2,2′-(ethylene­dioxy)­bis­(ethylamine) (<b>3a</b>), Jeffamine ED-600 (<b>3b</b>), 4,4′-oxidianiline (<b>3c</b>), and <i>p</i>-phenylene­diamine (<b>3d</b>). They react with bis­(<i>N</i>-carboxy­anhydrides) of aromatic β-amino acid (N-unsubstituted bis­(benzoxazine-2,4-diones)) yielding the corresponding semiaromatic polyamides (<b>4a</b>–<b>4c</b>). The obtained free amino groups were modified with 2-isocyanatoethyl methacrylate. These methacryl-functionalized polyamides can be cross-linked in the presence of <i>N</i>,<i>N</i>-dimethyl­arylamide via free radical polymerization

Access to Amphiphilic <i>Cis</i>-Configurated Polyamide‑3 Using Alcohols as Initiators

The synthesis of polyamide-3 from 4a,5,8,8a-tetrahydro-1<i>H</i>-benzo­[<i>d</i>]­[1,3]­oxazine-2,4-dione (β-NCA, <b>1</b>) using methanol, dye (Disperse Red 13), and poly­(ethylene glycol) as initiator is described. The ring-opening polymerization under release of CO₂ produces polyamides-3 with definite terminal groups, high purity, and relatively narrow dispersity. This route was used for preparation of block copolymers from as an example

UV Light and Temperature Responsive Supramolecular ABA Triblock Copolymers via Reversible Cyclodextrin Complexation

A novel triblock macromolecular architecture based on cyclodextrin (CD) complexation is presented. A CD-functionalized biocompatible poly­(<i>N</i>-(2-hydroxypropyl)­methacrylamide) (PHPMA) building block (3800 ≤ <i>M</i>_n ≤ 10 600 g mol^–1; 1.29 ≤ <i>Đ</i>_M ≤ 1.46) and doubly guest-containing poly­(<i>N</i>,<i>N</i>-dimethylacrylamide) (PDMAAm) (6400 ≤ <i>M</i>_n ≤ 15 700 g mol^–1; 1.06 ≤ <i>Đ</i>_M ≤ 1.15) and poly­(<i>N</i>,<i>N</i>-diethylacrylamide) (PDEAAm) (5400 ≤ <i>M</i>_n ≤ 12 100 g mol^–1; 1.11 ≤ <i>Đ</i>_M ≤ 1.33) segments were prepared via reversible addition–fragmentation chain transfer (RAFT) polymerization and subsequently utilized for the formation of a well-defined supramolecular ABA triblock copolymer. The block formation was evidenced via dynamic light scattering (DLS), nuclear Overhauser effect spectroscopy (NOESY), and turbidity measurements. Furthermore, the connection of the blocks was proven to be temperature responsive andin the case of azobenzene guestsresponsive to the irradiation with UV light. The application of these stimuli leads to the disassembly of the triblock copolymer, which was shown to be reversible. In the case of PDEAAm containing triblock copolymers, the temperature-induced aggregation was investigated as well

Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with <i>A. viscosus</i> on material A after 24h.

<p>Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with <i>A. viscosus</i> on material A after 24h.</p

Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with <i>A. viscosus</i> on material ST after 24h.

<p>Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with <i>A. viscosus</i> on material ST after 24h.</p

Poly-Pore hollow bead sorption material, unloaded (magnification 500 x).

<p>Poly-Pore hollow bead sorption material, unloaded (magnification 500 x).</p

Chemical formula of Methacryl-Irga.

<p>Chemical formula of Methacryl-Irga.</p