Macromolecular Materials and Engineering最新文献

In this work, 2-hydroxyethyl methacrylate (HEMA) is modified by ibuprofen and diclofenac as anti-inflammatory drugs to synthesize ibuprofen-HEMA and diclofenac-HEMA monomers. Then, poly(ibuprofen-HEMA-co-HEMA) (PIHH), poly(diclofenac-HEMA-co-HEMA) (PDHH), and poly(2-hydroxyethyl methacrylate) (PHEMA) particles are prepared by distillation precipitation polymerization. The morphology and size of the particles are investigated by dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM). It is observed that all particles are spherical and with sizes of 298.3 nm for PHEMA, 178.8 nm for PDHH, and 85.2 nm for PIHH, respectively. Doxorubicin drug is loaded into the prepared particles and the drug release behavior is investigated for all the particles at two different pH values of 7.4 and 5.3. The release of the drug in acidic pH is higher due to the better solubility of DOX in acidic environment and the faster release of DOX molecules from nanocarriers. The toxicity of particles is also investigated and it is observed that by loading the drug into the PHEMA particles, the release of the drug causes fewer toxic effects than in the free state (drug without any nanocarrier), and the presence of ibuprofen and diclofenac in the particles, that is, PIHH and PDHH, led to a significant reduction in the cytotoxicity.

Modern polymer-based technical components not only have to fulfill demanding mechanical-structural properties but need to integrate different functions to yield hybrid systems for complex operations. Typically, neither materials nor processing technologies are fully compatible with each other. The aim of the work is to combine the advantages of seemingly incompatible manufacturing processes such as high-volume injection molding (IM) and precision additive manufacturing to produce functional and customized hybrid materials. IM is widely used for polymer processing but stands against high investment costs for tailor-made molds with high-resolution features. They focus on overprinting of injection-molded parts made of thermoplastic polyurethane (TPU) with microstructures via projection-microstereolithography (PµSL) to generate hybrid polymer materials with spatially tailored stiffness, enabling selective reinforcement, resulting in an E modulus increase of 195% compared to mere IM-processed TPU. With that, the hybridization of processing methods is showcased to extend the product properties of polymer materials obtained via either IM or PµSL printing that have, prospectively, a maximum degree of individualization as well as a multitude of structural and functional features at the same time. To achieve optimum interfacial adhesion, the influence of surface roughness is studied, and reinforcement effects of different overprinted microstructure types are evaluated.

In this study, two green extraction methods are explored to valorize rice straw into cellulose fibers (CFs), namely subcritical water extraction (SWE) and combined ultrasound-heating treatment (USHT). The resultant fibers are, thereafter, successfully pretreated with (3-glycidyloxypropyl) trimethoxysilane (GPS) and incorporated at 3% wt into poly(butylene succinate) (PBS) by melt-mixing. The green composites are shaped into films by thermo-compression and characterized in terms of their performance for food packaging applications. The chemical analysis of the fibers reveals that SWE is more effective to selectively remove hemicelluloses than USHT, whereas silanization promotes the removal of lignin in both fiber types. Fiber incorporation, more notably in the case of the silanized fibers, restricts the movement of the PBS chains, indicating good interaction with the biopolyester matrix. In particular, CFs act as antinucleating agents in PBS, delaying both glass transition and crystallization from the melt phenomena and hindering crystal formation. Furthermore, the fibers mechanically reinforce and improve the oxygen barrier of the PBS films. The highest barrier enhancement is obtained for the thermo-compressed composite film with silanized fibers obtained by SWE, yielding a decrease of nearly 20% in the permeability to oxygen versus the unfilled PBS film.

With this issue of Macromolecular Materials and Engineering, celebrating 25 years of the journal, the editors, friends, and colleagues congratulate Prof. Rolf Mülhaupt on the occasion of his 70th birthday in September 2024. The broad range of topics assembled in this volume reflects the impressive scope of topics, Rolf Mülhaupt's research has addressed. It was briefly sketched how these have evolved from the different stations of his career in a previous editorial in a sister journal.^[1]

The ten years that have passed since this review of Rolf Mülhaupt's outstanding and unconventional scientific career have certainly held unexpected developments. Only a few days after the conference “Makromolekulares Kolloquium” in Freiburg in February 2020 honored him on the occasion of his upcoming formal retirement from his chair position at the Institute of Macromolecular Chemistry, public and academic life were shut down by a pandemic. Also, he was not spared from “remote teaching” in the following. His scientific curiosity and productivity are, of course, uncompromised, as also evidenced by his published oeuvre. Within the breadth of Rolf Mülhaupt's contributions, as an example of his interests in the past decade, it is certainly appropriate to highlight additive manufacturing, reflected in a review article that has been cited already more than 2500 times since its appearance in 2017.^[2] This topic—in which he was active very early on actually—has moved on to—among others—3D printing of polyolefins with his team. This again takes advantage of his development of “all-polyethylene” composites, which achieve outstanding material performance yet are also well processable, thereby providing improved circularity. Concerning the intensely discussed issue of polymer materials' circularity, the scientific community continues to benefit from Rolf Mülhaupt's to-the-point and sometimes sobering assessments of reality, for instance in “Green Polymer Chemistry and Bio-based Plastics: Dreams and Reality”,^[3] a highly cited perspective on this research area and its future options.

Together with all other authors that have contributed to this volume, and with the entire team of the Macromolecular journals, I congratulate Rolf Mülhaupt on the occasion of his anniversary and wish him continued delight in science in the years to come!