Polyethylene (PE), the plastic with the largest production volume globally (>110 million tons per year), is mainly used in short term applications. A high molecular weight PE with a carbon main chain is not biodegradable; however, its lower molecular weight oligomers (M∼500−1,000 g/mol) are reported to undergo microbial degradation. Therefore, there is an increasing interest in PE-like materials that can be degraded into shorter chain segments to augment the materials susceptible to biodegradation. This review highlights research concerning the introduction of hydrolysable repeating units, such as carboxylic esters, carbonates, phosphate esters, or acetal groups, into the PE main-chain. The strategy offers new opportunities in the design of PE-like materials with an enhanced ability to undergo controlled degradation, which can take place at the stage defined by the user and enables closed-loop chemical recyclability. This mini-review highlights typical examples of PE-like materials with hydrolytically labile groups in the main-chain and discusses the influence of such groups on the degradability of resulting polymers.

Poly(2-isopropenyl-2-oxazoline) hydrogels (PiPOx) and their silver-loaded counterparts (PiPOx-Ag) were investigated for antibacterial and dye adsorption performance in aqueous environments. Incorporation of Ag⁺ ions imparted broad-spectrum antimicrobial activity, leading to a reduction in bacterial counts of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus by 4.5-6 logarithmic units per 1 mL, as well as Klebsiella pneumoniae by 2.2 logarithmic units per 1 mL after 24 h in a time-kill assay under conditions simulating contaminated water systems. The antibacterial effect of PiPOx-Ag was attributed to the rapid release of Ag⁺ ions from the hydrogel network and their subsequent chemisorption onto bacterial cells, indicating that PiPOx acts as an efficient Ag⁺ delivery matrix in aqueous environments. To check the potential of PiPOx-Ag in water decolorizaton, the adsorption of selected dyes, including azo (methyl orange), thiazine (methylene blue), triphenylmethane (malachite green), and phenolic dyes (phenol red), was evaluated. The results revealed dye-dependent uptake, with maximum removal efficiencies of 12-15% at an initial dye concentration of 10 mg/L. PiPOx exhibited intrinsic adsorption capacity, which was further enhanced upon Ag⁺ incorporation. Overall, PiPOx-based hydrogels exhibit multifunctional behaviour, combining antimicrobial activity with selective dye adsorption, highlighting their potential for water remediation applications.

Hydrogels, after the rational design of their structure, can exhibit the properties (such as stiffness, pore size, viscoelasticity, degradability, presence of ligands, etc.) required for specific intended functions, making them versatile platforms for a variety of applications. This study evaluated the potential for the multidirectional use of hydrogels obtained from biocompatible polymers: poly(2-isopropenyl-2-oxazoline) (PiPOx) and selected polyesters (polylactide-PLA and polycaprolactone-PCL) as drug carriers, sorbents, antimicrobial hydrogels and plant growth supports. Hydrogels containing covalently attached drugs (probenecid, valproic acid, or ibuprofen) were synthesized through the cross-linking of suitably modified PiPOx with dicarboxyl PLA. The release of probenecid was subsequently monitored at 37 degrees C and pH 8.3 using UV/Vis spectroscopy. To evaluate the potential of these hydrogels for water purification, we conducted sorption tests using selected metal cations (Fe3+ and Cu2+) and dyes (crystal violet, acidic fuchsin) from aqueous solutions. Furthermore, the antimicrobial activity of the quercetin-loaded hydrogels was assessed using the agar diffusion method. Finally, we investigated the feasibility of employing these hydrogels as substrates for plant cultivation. The results obtained demonstrate that hydrogels composed of poly(2-isopropenyl-2-oxazoline) and aliphatic polyesters are functional materials with a wide range of potential applications.

Research on the degradability of polymeric materials and their facilitated decomposition after use may significantly contribute to addressing the problem of increasing environmental pollution. In this work, recyclable films based on ABA triblock copolymers containing polylactide A-blocks and easily degradable polydioxolane B-blocks were prepared and investigated. To obtain copolymers suitable for commercial applications, a large-scale synthesis procedure was developed, and the process capacity was scaled up to hundreds of grams per batch. The results show that, under the conditions used, the molar mass and composition of the copolymers can be readily controlled by adjusting the ratio of cyclic ester to the alpha,omega-hydroxy-terminated polyacetal macroinitiator in the ring-opening polymerisation (ROP) catalyzed by tin(II) octoate (Sn(Oct)2). To create copolymers with high potential for recovering recyclable compounds, a polyacetal block (7,000 g/mol) was combined with polyester blocks of varying lengths, whose molecular weights did not exceed 20,000 g/mol. Films formed from the studied copolymers were produced by compression moulding in a hot press and subsequently evaluated in detail for their thermal, barrier, and mechanical properties. Chemical recycling of the polymeric materials via depolymerization was examined using an acid catalyst at temperatures between 150 degrees C and 200 degrees C. We hypothesise that these novel films have strong potential to serve as next-generation recyclable materials, enabling the recovery of both the cyclic monomer and polylactide.

Poly(2-isopropenyl-2-oxazoline) hydrogels (PiPOx) obtained by crosslinking with HOOC-PEG-COOH and ethylenediaminetetraacetic acid diamonium salt (NH4-EDTA) were evaluated alongside their silver-loaded counterparts (PiPOx-Ag hydrogels) for antibacterial and dye adsorption performance in aqueous environments. Incorporation of Ag+ ions imparted broad-spectrum antimicrobial activity, leading to a reduction in bacterial counts of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecium, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus by 4.5-6 logarithmic units per 1 mL, as well as Klebsiella pneumoniae by 2.2 logarithmic units per 1 mL after 24 h in a time-kill assay under conditions simulating contaminated water systems. The antibacterial effect of PiPOx-Ag hydrogelswas attributed to the rapid release of Ag+ ions from the hydrogel network and their subsequent chemisorption onto bacterial cells, indicating that PiPOx acts as an efficient Ag+ delivery matrix in aqueous environments. To check the potential of PiPOx-Ag hydrogelsin water decolorizaton, the adsorption of selected dyes, including azo (methyl orange), thiazine (methylene blue), triphenylmethane (malachite green), and phenolic dyes (phenol red), was evaluated. The results revealed dye-dependent uptake, with maximum removal efficiencies of 12-15% at an initial dye concentration of 10 mg/L. PiPOx exhibited intrinsic adsorption capacity, which was further enhanced upon Ag+ incorporation. Overall, PiPOx-based hydrogels combine effective antimicrobial activity with measurable adsorption of selected dyes, indicating their potential as multifunctional materials for integrated water treatment applications.

Graft copolymers of polylactide and oligo(methyl methacrylate) (PLA-g-MMA) were synthesized by atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) using PLA containing 10 mol % of acetal units functionalized with bromine or chlorine moieties as a multisite macroinitiator. The ultimate aim was to improve the miscibility of PLA and PMMA by preparing graft copolymers. The MMA was chosen as a model vinyl monomer to investigate whether the presented method allows the synthesis of required copolymers with controlled topology and molecular masses. First, PLA-based multisite macroinitiators (M-n similar to 10,000 g mol(-1)) were obtained via the cationic (co)polymerization of L-LA (LA) and functionalized cyclic acetals (2-bromomethyl-1,3-dioxolane-BrDXL or 2-chloromethyl-1,3-dioxolane-ClDXL), carried out in the presence of ethylene glycol as an initiator and triflic acid as a catalyst. Subsequently, PLA-g-MMA with different compositions (containing 60-80 mol % of MMA) were obtained in the presence of the pendant-activated groups (chlorides or bromides) in the catalyst system consisting of copper halides (CuBr or CuCl) and N,N,N,N '',N ''-pentamethyldiethylenetriamine (PMDETA). The size exclusion chromatography (SEC) analysis revealed that the obtained PLLA-g-MMA molar mass was 12,000-23,000 g mol(-1). Differential scanning calorimetry (DSC) analysis of all prepared PLA-g-MMA copolymers revealed only one T-g ranging from 55 to 82 degrees C, which allows us to conclude the miscibility of the components forming the copolymer. Finally, the thermal properties, susceptibility to degradation, and conditions for forming copolymeric particles were investigated.

Polymers of higher cyclic formals containing alternating oxymethylene (OM) units and a few oxyethylene (EO) units can be considered as components in solid polymer electrolytes.

Molar mass correction coefficients (cc) were determined for calculating the absolute molar masses of polylactide (PLA), polycaprolactone (PCL), and poly(2,2-dimethyltrimethylene carbonate) (PDTC) in the range of 2,5-190 kg/mol, using calibration based on polystyrene standards (PS). Linear PLAs, PCLs, and PDTCs with a wide range of molar masses were synthesized using tin (II) octoate and diol as a catalyst/initiator system. Size Exclusion Chromatography (SEC) coupled with a Refractive Index detector (SEC-RI) or a Multi-Angle Laser Light Scattering detector (SEC-MALLS) was utilized to determine the relative molar mass or absolute molar mass of the samples under investigation. Additionally, for comparison, the absolute molar mass of low molar mass PLA, PCL, or PDTC was calculated based on end-group analysis using the H-1 NMR method. Correction coefficients were subsequently calculated by comparing the molar mass obtained from SEC-MALLS and SEC-RI. The calculated correction coefficients ranged from 0.40 to 0.87 and increased with the rising molar mass of the polymers. The derived equation could be used to evaluate the absolute molar masses from PS standards over a broad range for the analyzed polymers.

In this study, porous networks were efficiently prepared by crosslinking hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx) with dicarboxylic polyesters (HOOC-PLA-COOH or HOOC-PCL-COOH) in the presence of sodium chloride as a water-soluble porogen. Importantly, by using a relatively simple synthetic protocol, the resulting spongy materials were freely formed to the desired size and shape while maintaining stable dimensions. According to the SEM data, the porous 3D structure can be altered by the pore dimensions, which are dependent on the porogen crystal size. After porosity characterization, the mechanical properties were also evaluated via uniaxial compression and tensile tests. The porous networks formed hydrogels with a high water absorption capacity. Finally, after showing cytocompatibility by the MTT assay, we also demonstrated the applicability of the porous hydrogels as scaffolds for cell cultivation. The presented results suggest that this type of hydrogels is a promising material for tissue engineering. Porous networks were efficiently prepared by crosslinking hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx) with dicarboxylic polyesters (HOOC-PLA-COOH or HOOC-PCL-COOH) in the presence of sodium chloride as a water-soluble porogen.

New functionalized lactide copolymers containing acetalunits wereprepared for the first time in a controlled manner that enabled theregulation of the number of reactive groups introduced into the polyesterchain. The presence of functional groups in the copolymer backboneprovided chemical modification sites, and the nature of the acetalunit affected the material degradability. First, paraformaldehydewas reacted with selected diols containing reactive pendant groups(3-allyloxypropane-1,2-diol and 3-chloropropane-1,2-diol), which wascatalyzed by p-toluenesulfonic acid, to synthesizenew cyclic acetals with different functionalities (allyl- or chloro-).In addition, using butane-1,4-diol, a nonfunctionalized seven-memberedcyclic acetal (dioxepane) was obtained for comparative studies. Inthe next step, the prepared cyclic acetals were used for cationiccopolymerization with lactide in the presence of glycol as an initiatorand triflic acid as a catalyst. Different temperatures (-15,2, and 30 & DEG;C) and copolymerization times (24, 48, 72, and 192h) were investigated to produce copolyesters with variable contentsof acetal units in the range of 5-27%. The copolymers'structure and molar masses were carefully investigated using H-1, C-13 NMR, 2D NMR, and size-exclusion chromatography.Moreover, the ability of functionalized copolymers to perform postmodifications was also proven by the reaction with sodium azide andpropanethiol. Finally, we speculate that structurally diverse groupscan be attached to the copolyester chain, fine-tuning the on-demandproperties, which could rapidly expand the library of polylactide-basedmaterials.

Supramolecular hydrogels were obtained through cross-linking PVA with quercetin (Q) since it exhibits antimicrobial and antifungal properties apart from forming hydrogen bonds with PVA. This strategy allows for the preparation of the hydrogels with desired physicochemical properties and the ability for the elimination of bacterial and fungal strains. Most importantly, the hydrogels exhibit an inhibitory effect against fluconazole-resistant yeast strains. Apart from hydrogel's antimicrobial properties, the color of the hydrogels gradually changes depending on the bacteria strains. This feature indicates that these Q-crosslinked hydrogels can also be a sensors for different bacteria strains. All these advantageous features of hydrogels composed of supramolecular networks predispose their applications as highly effective antimicrobial and antifungal materials for food preservation or wound healing.

Polylactide (PLA) is a biocompatible polyester that can be obtained by polycondensation of lactic acid or the ring-opening polymerization (ROP) of lactide [...].

To promote facile and efficient synthesis of segmented covalent networks, we developed a cross-linking process with reactive polymeric components in a system without catalysts or side products. To achieve the direct formation of amphiphilic networks, an addition reaction was performed between the polyesters containing carboxyl terminal groups with pendant groups distributed along poly(2-isopropenyl-2-oxazoline) chains. Covalent cross-linking was achieved from predetermined amounts of components dissolved in DMSO at 140 °C. To tune the properties of the resulting networks, the composition and length of the polyester segments and the degree of cross-linking were changed in the feed. The chemical structure of the networks was characterized using Fourier transform infrared-attenuated total reflection spectroscopy and 13C magic-angle spinning NMR. The swelling ability of the formed networks was investigated in aqueous and organic media. Moreover, mechanical properties were tested during uniaxial compression. The cytocompatibility of the scaffolds was confirmed by MTT assay. Through the results obtained, the first report describing the cross-linking of polyesters on hydrophilic PiPOx was provided to prepare new, biocompatible materials with tuneable properties that are promising for potential biomedical applications.

The resistance of microorganisms against commonly used antibiotics is becoming an increasingly important problem in the food and pharmaceutical industries. Therefore, the development of novel bactericidal agents, as well as the design of drug delivery systems based on materials composed of biocompatible and biodegradable building blocks, has attracted increasing attention. To address this challenge, microparticles composed of l-lactide homopolymer and l-lactide/1,3-dioxolane (co)polymers loaded with quercetin (Q) were fabricated by using a microfluidic technique. This method enables the preparation of homogeneous particles with sizes ranging from 60 to 80 µm, composed of degradable semicrystalline or amorphous (co)polyesters. The microencapsulation of Q in a (co)polymeric matrix enables prolonged release of the antimicrobial agent. The antibacterial properties of the obtained biocompatible microparticles are confirmed by the agar diffusion plate method for various bacterial strains. Therefore, Q-loaded microparticles can have important applications in food preservation as a novel antimicrobial system.

Poly(2-isopropenyl-2-oxazoline) has attracted growing interest as a reactive polymer that can be used as a starting material for the construction of more complex structures.

Polylactide (PLA) is one of the most important polymer and is used for the production of biodegradable materials. High-molecular-weight PLA is applied mainly for the manufacture of disposable consumer goods. In contrast, lower- or medium-molecular-weight polymers usually find applications in medicine for controlled drug release systems or implants. Most importantly, the properties of low- and medium-molecular-weight PLAs are strongly dependent on the nature of the end group. To adequately address this issue, this review summarizes the various structures of PLA end groups as well as the methods of their modification and characterization. The appropriate functionalization of PLA macromolecules is extremely important since it allows control of hydrolytic and thermal degradation, PLA self-assembly, and their interactions with nanosized particles or metal ions. In addition, the drug release from PLA-based particles can be adjusted by end group modification. The improved end-use properties of PLA-based materials by chain-end functionalization are desirable for their applications as drug delivery systems, tissue engineering, and electronic sensors. Therefore, the advantages and limitations of PLA end group modification are discussed. Special attention is given to the preparation of supramolecular PLA materials with the ability to respond to even mild environmental alteration or to undergo self-healing. Finally, an outlook regarding establishing the influence of PLA end groups on the properties of PLA-based materials is presented, and perspectives of this emerging area are discussed.

Novel, degradable amphiphilic ABA triblock copolymers with a polyacetal chain as the hydrophilic internal block and polyesters as external hydrophobic segments were designed and prepared for the first time in a controlled manner.

Novel polymer networks composed of biocompatible, hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx), poly(ethylene oxide) (PEO), and selected biologically active compounds (cinnamic acid, benzoic acid or eugenol) were developed for potential antimicrobial applications. The applied crosslinking method, based on the addition reaction between oxazoline pendant groups and chosen reagents containing carboxyl functions, is relatively facile, free from by-products, and thus well suited for biomaterial preparation. The one-step synthesis enabled efficient network formation with high gel contents (>90%). The chemical structure of the newly synthesized networks was characterized using Fourier Transform Infrared-attenuated Total Reflection spectroscopy (FTIR-ATR) and 13C Magic-Angle Spinning (MAS) NMR. To evaluate the suitability for biomedical applications, swelling in water and the mechanical properties of the networks were investigated. The antimicrobial efficacy of the prepared hydrogels was tested in neutral medium both by the agar diffusion method and in the liquid culture against Gram-positive and Gram-negative strains: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Enterobacter cloaceae. All the tested hydrogels showed an antimicrobial effect in the direct contact zone. Moreover, the eugenol loaded hydrogel expressed a broader bacteriostatic effect inhibiting microorganism growth beyond the contact zone. These form-stable hydrogels with antibacterial properties may be of interest for designing materials dedicated to biomedical applications.

The reaction of poly(hydromethylsiloxane-co-methylphenylsiloxane) with zirconium (IV) n-propoxide in dry toluene leads to extensive scission of the siloxane chain and conversion of Si-H groups. These processes produce oligomeric siloxanes and organosilanes containing moisture sensitive propoxy and siloxy-zirconate groups. The obtained post-reaction solution of zirconium containing heterosiloxane oligomers is stable under anhydrous conditions for several weeks. However, its exposure to moisture initiates the hydrolytic condensation of the reactive groups leading to cross-linking and the formation of a siloxane-zirconium composite. Spin coating of the siloxane-zirconium prepolymer followed by exposure to moisture produces thin films with excellent light transparency and increased refractive index. The final coatings are characterized by ellipsometry, UV-Vis, IR, and 29 Si MAS NMR spectroscopies.

Herein, we report the first example of cationic ring-opening copolymerization of 5-membered cyclic acetal (1,3-dioxolane (DXL)) with l-lactide (LA) to afford polylactide containing acetal units.