Polymerization Of Caprolactone Research Articles

A multistep (semi)-continuous biocatalytic setup for the production of polycaprolactone.

Biocatalysis has gained increasing importance as an eco-friendly alternative for the production of bulk and fine chemicals. Within this paradigm, Baeyer Villiger monoxygenases (BVMOs) serve as enzymatic catalysts that provide a safe and sustainable route to the conventional synthesis of lactones, such as caprolactone, which is employed for the production of polycaprolactone (PCL), a biocompatible polymer for medicinal applications. In this work, we present a three-step, semi-continuous production of PCL using an entirely biocatalytic process, highlighting the merits of continuous manufacturing for enhancing biocatalysis. First, caprolactone is produced in batch from cyclohexanol using a coenzymatic cascade involving an alcohol dehydrogenase (ADH) and BVMO. Different process parameters and aeration modes were explored to optimize the cascade's productivity. Secondly, the continuous extraction of caprolactone into an organic solvent, needed for the polymerization step, was optimized. 3D-printed mixers were applied to enhance the mass transfer between the organic and the aqueous phases. Lastly, we investigated the ring-opening polymerization of caprolactone to PCL catalyzed by Candida antarctica lipase B (CAL-B), with a focus on eco-friendly solvents like cyclopentyl-methyl-ether (CPME). Space-time-yields up to 58.5 g L-1 h-1 were achieved with our overall setup. By optimizing the individual process steps, we present an efficient and sustainable pathway for PCL production.

Amphiphilic block copolymers bearing fatty acid derivatives as vehicles for THC in the development of analgesic oral formulations

Cannabis-based therapeutics have gained increasing attention for their potential health benefits; however, the efficient administration of hydrophobic constituents such as Δ9-tetrahydrocannabinol (THC) remains a challenge. This study explores a novel approach employing amphiphilic block copolymers to encapsulate a THC-rich extract to enhance its analgesic effect. The synthesis of amphiphilic block copolymers involves sequential ring-opening polymerization of caprolactone and a cyclic carbonate with pedant alkyne moieties. This is followed by an alkyne/azide click reaction with fatty acid derivatives. These copolymers are used to encapsulate the THC-rich extract. These extract-loaded micelles exhibit nanometric sizes, uniform distribution, and high colloidal stability in simulated gastrointestinal fluids. The release kinetic assessment of THC from the micelles displays controlled and sustained profiles, which are influenced by the hydrophobic nature of the copolymer core. In vivo evaluations using a murine model revealed the safety of micellar formulations, with minimal impact on behavior and organ health. Remarkably, micellar systems demonstrated prolonged analgesic effects in both mechanical and chemical pain models, outperforming nonencapsulated THC. This study introduces a pioneering approach to cannabis-based analgesics with prolonged activity, harnessing the potential of the tailored design of amphiphilic block copolymers to enhance the delivery and efficacy of hydrophobic cannabinoids.

Poly(ε-caprolactone)-poly(ethylene glycol) Tri-Block Copolymer as Quercetin Delivery System for Human Colorectal Carcinoma Cells: Synthesis, Characterization and In Vitro Study.

Quercetin is a hydrophobic molecule with short blood circulation times and instability. The development of a nano-delivery system formulation of quercetin may increase its bioavailability, resulting in greater tumor suppressing effects. Triblock ABA type polycaprolactone-polyethylenglycol- polycaprolactone (PCL-PEG-PCL) copolymers have been synthetized using ring-opening polymerization of caprolactone from PEG diol. The copolymers were characterized by nuclear magnetic resonance (NMR), diffusion-ordered NMR spectroscopy (DOSY), and gel permeation chromatography (GPC). The triblock copolymers self-assembled in water forming micelles consisting of a core of biodegradable polycaprolactone (PCL) and a corona of polyethylenglycol (PEG). The core-shell PCL-PEG-PCL nanoparticles were able to incorporate quercetin into the core. They were characterized by dynamic light scattering (DLS) and NMR. The cellular uptake efficiency of human colorectal carcinoma cells was quantitatively determined by flow cytometry using nanoparticles loaded with Nile Red as hydrophobic model drug. The cytotoxic effect of quercetin-loaded nanoparticles was evaluated on HCT 116 cells, showing promising results.

Ring Opining polymerization of caprolactone And Antibacterial activity by Mixed Ligand of Metal(II) and (III)

Ring Opining polymerization of caprolactone And Antibacterial activity by Mixed Ligand of Metal(II) and (III)

Influence of Block Copolymer Concentration and Resin Crosslink Density on the Properties of UV‐Curable Methacrylate Resin Systems

AbstractAdditive manufacturing is on the verge of replacing established processes in dentistry, as it offers the possibility of manufacturing individual parts simply and cost‐effectively. Due to its suitability for a wide variety of materials and, above all, its high precision, the focus is currently on stereolithographic processes. Intrinsic brittleness of the used multifunctional acrylic monomers remains however one of the major challenges. One promising concept is the use of block copolymers (BCPs) guaranteeing minor effects on 3D‐printing processing and UV‐curing due to initially at least partial solubility, and hence low viscosity impact. A polycaprolactone‐polysiloxane (PCL‐PDMS‐PCL) triblock copolymer is synthesized via ring‐opening polymerization of caprolactone and used in radical UV‐cured methacrylic resin systems. Small angle X‐ray scattering measurements reveal the self‐assembly of the BCPs to objects of around 20 nm prior to curing. Subsequently, thermo‐mechanical characterization is carried out by dynamic mechanical analysis, flexural testing, and fracture toughness measurements (KIC). Transmission electron microscopy and scanning electron microscopy micrographs show a homogenous distribution of the BCPs and effective toughening via cavitation and shear yielding. The influence of the crosslink density on the toughness and the high effectiveness of block copolymers for improving fracture toughness is clearly shown.

3D printed PCLA scaffold with nano‐hydroxyapatite coating doped green tea EGCG promotes bone growth and inhibits multidrug‐resistant bacteria colonization

Objectives3D‐printing scaffold with specifically customized and biomimetic structures gained significant recent attention in tissue engineering for the regeneration of damaged bone tissues. However, constructed scaffolds that simultaneously promote bone regeneration and in situ inhibit bacterial proliferation remains a great challenge. This study aimed to design a bone repair scaffold with in situ antibacterial functions.Materials and MethodsHerein, a general strategy is developed by using epigallocatechin‐3‐gallate (EGCG), a major green tea polyphenol, firmly anchored in the nano‐hydroxyapatite (HA) and coating the 3D printed polymerization of caprolactone and lactide (PCLA) scaffold. Then, we evaluated the stability, mechanical properties, water absorption, biocompatibility, and in vitro antibacterial and osteocyte inductive ability of the scaffolds.ResultsThe coated scaffold exhibit excellent activity in simultaneously stimulating osteogenic differentiation and in situ resisting methicillin‐resistant Staphylococcus aureus colonization in a bone repair environment without antibiotics. Meanwhile, the prepared 3D scaffold has certain mechanical properties (39.3 ± 3.2 MPa), and the applied coating provides the scaffold with remarkable cell adhesion and osteogenic conductivity.ConclusionThis study demonstrates that EGCG self‐assembled HA coating on PCLA surface could effectively enhance the scaffold's water absorption, osteogenic induction, and antibacterial properties in situ. It provides a new strategy to construct superior performance 3D printed scaffold to promote bone tissue regeneration and combat postoperative infection in situ.

Development and Validation of PEG‐PCL Based Nanoformulation of Rosiglitazone and Evaluation of its Brain Selectivity in Mice Model of Alzheimer’s disease

AbstractBackgroundType‐2 Diabetes Mellitus and insulin resistance increases the risk of Alzheimer’s disease (AD). Recent studies highlighted the role of peroxisome proliferator‐activated receptor‐gamma (PPAR‐γ) in modulation of AD. This study was designed to investigate the effect of rosiglitazone alone or in its nanoformulated form for an effective drug delivery in mice model of AD.MethodAD mice model was developed by intracerebroventricular (ICV) administration of streptozotocin (STZ). PEG‐PCL polymer was synthesized using ring opening polymerization of caprolactone with methoxy‐PEG as a macroinitiator and stannousoctoate as catalyst. Nanoformulation of rosiglitazone was developed using emulsion‐diffusion‐solvent evaporation method. Nanoformulation was evaluated by Scanning electron microscopy, particle size analyzer and HPLC method. Cognitive functions were evaluated by passive avoidance task, object recognition task and Morris water maze test. Amyloid beta (Aβ) and phosphorylated tau (p‐tau) level were assessed by ELISA, level of oxidative stress and pro‐inflammatory cytokines like tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were measured in hippocampus homogenates and the expression level of CREB, BDNF, GDNF, NGF were assessed by RT‐PCR method.ResultThe rosiglitazone nanoformulation was observed within a range of 70±10 nm in size and the entrapment efficiency of rosiglitazone was 70±5%. The ICV‐STZ mice showed significant features of cognitive abnormalities. The mice treated with rosiglitazone and its formulation improved cognition, attenuated the elevated level of Aβ and p‐tau along with pro‐inflammatory cytokines‐TNF‐α and IL‐6 and oxidative stress was altered when compared with disease control animals. Moreover, these changes occurred concurrently with an increased expression level of BDNF, GDNF and NGF.ConclusionNanoformulation of rosiglitazone imparted significant neuroprotective efficacy with greater amounts being observed in the brain at a lower dose compared to its free form.

Catalytic Activity of Various β‐Diketiminate Zinc Complexes toward the Ring‐Opening Polymerization of Caprolactone and Derivatives

AbstractThe ring‐opening polymerization (ROP) of lactones is mainly catalyzed by tin(II) octanoate Sn(Oct)2, due to its efficiency and easy handling despite the toxic issues of tin. Herein, two novel dinuclear bis(β‐diketiminate) complexes with flexible alkylene bridging groups (1,2‐ethylene and 1,3‐propylene) and biocompatible zinc centers are introduced. The complexes are obtained by deprotonation of the protio‐ligands with Zn(HMDS)2 and fully characterized. Afterwards the complexes are studied regarding their catalytic activity towards the ROP of caprolactones. Briefly, ε‐caprolactone (CL), ε‐phenyl‐ε‐caprolactone (phCL) and ε‐methyl‐ε‐caprolactone (meCL) with and without benzyl alcohol (BnOH) as initiator in toluene are homopolymerized and compared to the known dinuclear 1,4‐phenylene bridged bis(β‐diketiminate) zinc catalyst and the mononuclear counterpart. Thereby, the catalysts are classified upon their efficiency by in situ IR measurements, selectivity, and polymerization control by size exclusion chromatography (SEC) of samples, which are terminated at 60% conversion. The novel zinc catalysts prevent Sn(Oct)2 typical molar mass broadening, show slower reaction rates than 1,4‐phenylene bridged bis(β‐diketiminate) and improve control compared to the mononuclear relative. However, a drastic loss of polymerization control resulting in high molar masses and polydispersities occurrs in the absence of BnOH. Furthermore, these complexes allow the ROP of phCL but are inactive for meCL.

Stable abnormal N-heterocyclic carbenes and their applications.

Although N-heterocyclic carbenes (NHCs) have been known as ligands for organometallic complexes since the 1960s, these carbenes did not attract considerable attention until Arduengo et al. reported the isolation of a metal-free imidazol-2-ylidene in 1991. In 2001 Crabtree et al. reported a few complexes featuring an NHC isomer, namely an imidazol-5-ylidene, also termed abnormal NHC (aNHCs). In 2009, it was shown that providing to protect the C-2 position of an imidazolium salt, the deprotonation occurred at the C-5 position, affording imidazol-5-ylidenes that could be isolated. Over the last ten years, stable aNHCs have been used for designing a range of catalysts employing Pd(ii), Cu(i), Ni(ii), Fe(0), Zn(ii), Ag(i), and Au(i/iii) metal based precursors. These catalysts were utilized for different organic transformations such as the Suzuki-Miyaura cross-coupling reaction, C-H bond activation, dehydrogenative coupling, Huisgen 1,3-dipolar cycloaddition (click reaction), hydroheteroarylation, hydrosilylation reaction and migratory insertion of carbenes. Main-group metal complexes were also synthesized, including K(i), Al(iii), Zn(ii), Sn(ii), Ge(ii), and Si(ii/iv). Among them, K(i), Al(iii), and Zn(ii) complexes were used for the polymerization of caprolactone and rac-lactide at room temperature. In addition, based on the superior nucleophilicity of aNHCs, relative to that of their nNHCs isomers, they were used for small molecules activation, such as carbon dioxide (CO2), nitrous oxide (N2O), tetrahydrofuran (THF), tetrahydrothiophene and 9-borabicyclo[3.3.1]nonane (9BBN). aNHCs have also been shown to be efficient metal-free catalysts for ring opening polymerization of different cyclic esters at room temperature; they are among the most active metal-free catalysts for ε-caprolactone polymerization. Recently, aNHCs successfully accomplished the metal-free catalytic formylation of amides using CO2 and the catalytic reduction of carbon dioxide, including atmospheric CO2, into methanol, under ambient conditions. Although other transition metal complexes featuring aNHCs as ligand have been prepared and used in catalysis, this review article summarize the results obtained with the isolated aNHCs.

Increasing the hydrophilicity of star‐shaped amphiphilic co‐networks by using of PEG and dendritic s‐PCL cross‐linkers

New hyperbranched hydrophobic cross‐linkers with peripheral azide groups were synthesized as follows: First, star‐shaped polycaprolactones (sPCL) were synthesized by ring‐opening polymerization of caprolactone in the presence of pentaerythritol and tin (II) octoate. In the next step, sequential acrylation, Micheal addition, tosylation, and azidation by acryloyl chloride, diethanol amine, tosyl chloride, and sodium azide were respectively exploited to synthesize azide‐functionalized hyperbranched star‐shaped polycaprolactones which were named sPCL‐acrylate‐diethanolamine‐azide (sPCL‐AC‐DEA‐N3) and sPCL‐acrylate‐diethanolamine‐acrylate‐diethanolamine‐azide (sPCL‐AC‐DEA‐AC‐N3). All steps were thoroughly characterized by FT‐IR and 1H NMR spectroscopy. The GPC analysis showed that the molecular weight of sPCL increased after two azide functionalizations. Amphiphilic hydrogels based on sPCL‐AC‐DEA‐N3 (Mn = 8130 g/mol) and sPCL‐AC‐DEA‐AC‐N3 (Mn = 10112 g/mol) with linear alkyne‐terminated polyethylene glycols (PEG) (Mn = 2000, 4000, and 6000 g/mol) were synthesized through click coupling between azide and alkyne groups. In both hydrogels, the swelling ratio increased by increasing the molecular weight of PEG. The obtained results showed that the branching of the cross‐linker, significantly affected the swelling ratio of hydrogels. For instance, the swelling ratio of sPCL‐AC‐DEA‐AC‐N3 and PEG‐6000 (Q = 900) was higher than sPCL‐AC‐DEA‐N3 and PEG‐6000 (Q = 600). Despite the high cross‐linking density of sPCL‐AC‐DEA‐AC‐DEA‐N3–based hydrogels, the amount of released theophylline was higher than sPCL‐AC‐DEA‐N3–based hydrogels, due to the high content of PEG in these hydrogels.

Non-Einstein Viscosity Phenomenon of Acrylonitrile-Butadiene-Styrene Composites Containing Lignin-Polycaprolactone Particulates Highly Dispersed by High-Shear Stress.

Lignin powder was modified via ring-opening polymerization of caprolactone to form a lignin–polycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrile–butadiene–styrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to the general extruded composite one (4270 Pa·s) at 1 s–1 and 210 °C. This is due to the conformational rearrangement and the increased free volume of ABS molecular chains in the vicinity of LPCL particulates. This was supported by the decreased glass transition temperature (Tg, 83.7 °C) of the LPCL/ABS composite specimens, for example, giving a 21.8% decrement compared to that (107 °C) of the neat ABS by the incorporation of 10 wt % LPCL particulates in ABS. The LPCL particulate morphology, damping characteristics, and light transmittance of the developed composites were thoroughly investigated at various levels of applied shear rates and mixing conditions. The non-Einstein rheological phenomena stemming from the incorporation of LPCL particulates suggest an interesting plasticization methodology: to improve the processability of high-loading filler/polymer composites and ultra-high molecular weight polymers that are difficult to process because of their high viscosity.

Chemoenzymatic Synthesis of Nitrogen Polymers with Biomedical Applications Catalyzed by Lipases.

The application of Candida antarctica lipase B as catalyst in the synthesis of two examples of nitrogen polymers is described. Firstly, we report a novel linear polyamidoamine oligomer, obtained by polymerization of ethyl acrylate and N-methyl-1,3-diaminopropane, catalyzed by Candida antarctica lipase B immobilized on polypropylene. The second part of the chapter describes an efficient route for the synthesis of a novel β-peptoid oligomer with hydroxyalkyl pendant groups in the nitrogen atom, through the polymerization of ethyl N-(2-hydroxyethyl)-β-alaninate catalyzed by Candida antarctica lipase B physically adsorbed within a macroporous poly(methyl methacrylate-co-butyl methacrylate) resin. Moreover, two derivatives of the β-peptoid oligomer were prepared: by acetylation and by grafting polycaprolactone. This last process was performed through ring-opening polymerization of caprolactone from the β-peptoid pendant hydroxyl groups and afforded a brush copolymer. The products were blended with polycaprolactone to make films by solvent casting. The inclusion of the acyl derivatives of the β-peptoid to polycaprolactone affected the morphology of the film yielding micro- and nanostructured patterns. The obtained products showed biomedical applications.

Preparation of Pendant Group-Functionalized Diblock Copolymers with Adjustable Thermogelling Behavior.

Recently, several thermogelling materials have been developed for biomedical applications. In this study, we prepared methoxy polyethylene glycol (MPEG)-b-(poly(ε-caprolactone)-ran-poly(2-chloride-ε-caprolactone) (PCL-ran-PfCL)) (MP-Cl) diblock copolymers at room temperature via the ring-opening polymerization of caprolactone (CL) and 2-chloride-ε-caprolactone (fCL) monomers, using the terminal alcohol of MPEG as the initiator in the presence of HCl. MPEG-b-(poly(ε-caprolactone)-ran-poly(2-azide-ε-caprolactone) (PCL-ran-PCL-N3)) (MP-N3) was prepared by the reaction of MP-Cl with sodium azide. MPEG-b-(poly(ε-caprolactone)-ran-poly(2-amine-ε-caprolactone) (PCL-ran-PCL-NH2)) (MP-NH2) was subsequently prepared by Staudinger reaction. MP-Cl and MP-N3 showed negative zeta potentials, but MP-NH2 had a positive zeta potential. MP-Cl, MP-N3, and MP-NH2 solutions formed opaque emulsions at room temperature. The solutions exhibited a solution-to-hydrogel phase transition as a function of the temperature and were affected by variation of the chloride, azide, and the amine pendant group, as well as the amount of pendant groups present in their structure. Additionally, the phase transition of MP-Cl, MP-N3, and MP-NH2 copolymers was altered by pendant groups. The solution-to-hydrogel phase transition was adjusted by tailoring the crystallinity and hydrophobicity of the copolymers in aqueous solutions. Collectively, MP-Cl, MP-N3, and MP-NH2 with various pendant-group contents in the PCL segment showed a solution-to-hydrogel phase transition that depended on both the type of pendant groups and their content.

Harnessing synergies in tin-clay catalyst for the preparation of poly(ε-caprolactone)/halloysite nanocomposites

The first example of synergistic alkynyl-tin initiated ring-opening polymerization of cyclic ester in the presence of nanotubular silica particles is herein reported. Hydroxyl groups on the halloysite (HNTs) surface act as initiators for caprolactone polymerization and the resulting polymers are covalently grafted to the HNTs. The covalent anchorage of the poly(ε-caprolactone) (PCL) backbone to the HNTs ensures a high degree of interpenetration at the hybrid interface thereby allowing long-term stability of the PCL-grafted-HNTs suspension. Scanning electron microscopy analyses showed the uniform dispersion of the HNTs filler within the PCL matrix. The melt viscosity of the poly(ε-caprolactone)/HNTs composites decreases with increasing clay content. Thermal stability and microindentation hardness properties of the resulting nano-composites were significantly improved, as compared to native, non-reinforced PCL.

Synthesis and Characterization of Bridged Polysilsesquioxane Nanoparticles and Their Nanocomposites with Polycaprolactone by UV Irradiation

Spherical bridged polysilsesquioxane nanoparticles with thiol groups (BPS-SH) were prepared by the reduction of BPS with disulfide groups after the base-catalyzed hydrolysis and condensation reaction of bis(triethoxysilylpropyl)disulfide. The average size of BPS was around 100∼300 nm. Hydroxyethyl methacrylate (HEMA)-initiated polycaprolactone (PCL) was synthesized by ring-opening polymerization of caprolactone under the co-initiation of HEMA and Sn(Oct)2. New nanocomposites of BPS-SH and HEMA-PCL were fabricated by the photo-induced chemical reaction under a photoradical generator and ultraviolet light. BPS was fully and continuously covered with PCL, which resulted in the rough surface of BPS nanoparticles as well as the connected BPS nanoparticles together.

Ring-opening polymerization of caprolactone using novel polyaniline salt catalyst

Hybrid composite of polyaniline metal oxide composite, polyaniline-dodecyl hydrogen sulfate salt with ferric oxide, was prepared for the first time via simple one-step process of oxidizing aniline with ferric tris(dodecyl sulfate). Ferric tris(dodecyl sulfate) acts as an oxidant, emulsifier, dopant for polyaniline and also source of ferric oxide. Polyaniline salt composites were prepared via aqueous, emulsion, and interfacial polymerization pathways. Polyaniline salt composite was successfully demonstrated as polymer based solid acid catalysts in the ring-opening polymerization of e-caprolactone for the first time. This methodology gave low molecular weight poly(e-caprolactone) (MW-4035) with highly crystalline polymer of flower petals like morphology in 52 wt% yield (with respect to the amount of e-caprolactone used). Advantages of this methodology are the use of easily synthesizable, easily handlable, recyclable, cheaper, and eco-friendly nature of the catalyst. POLYM. ENG. SCI., 55:2245–2249, 2015. © 2015 Society of Plastics Engineers

Lanthanocene Diolate Complexes: Synthesis, Structures and Catalytic Property for ε‐Caprolactone Polymerization

AbstractReaction of LnCl3 first with three equivalent of C5H5Na in THF, then with one equivalent of N‐phenyldiethanolamine in THF‐DME afforded complexes of {[(C5H5)Ln((‐OCH2CH2)2N(C6H5)]4((4‐Cl)}[Na(DME)4] (Ln=Sm (1), Yb (2)), being characterized by infrared spectra, elemental analyses and X‐ray crystallography. They are ionic pair compounds. The anionic part is a cluster, which can be viewed as a cyclic tetramer with four (C5H5)Ln units bridged by four pairs of OR groups, forming a pinwheel structure. Both the complexes can catalyze the ring‐opening polymerization of ε‐caprolactone under mild conditions, and complex 1 is more active than complex 2. The polymerization accords with one order reaction kinetics for monomer concentration. The molecular weight increases with the yield increasing, and the molecular weight distribution is rather narrow (1.19<PDI<1.29).

Photothermal conversion of carbon nanohorns enhancing caprolactone polymerization

Photothermal conversion of nanocarbons has potential applications in medical and energy engineering. It is expected that the photothermal conversion of tubular nanocarbons can thermally enhance polymer formation on their surfaces and insides. We show in this report that light irradiation enhanced the catalytic polymerization of caprolactone (CL) on tubular carbon nanohorns, and polycaprolactone (PCL) was formed on the outside and, more abundantly, inside the carbon nanohorns. The PCL particles were of nanometer size, which indicated another unique effect of this method of preparation. The abundant PCL preparation inside the nanohorns was probably caused by the confinement of CL molecules and thermal energies inside the nanohorns, which could enhance the polymerization of CLs. Other nanocarbons that had photothermal conversion properties would similarly enhance polymerization and other chemical reactions to provide unique methods of synthesizing materials.

Super-tough functionalized graphene paper as a high-capacity anode for lithium ion batteries

Abstract A super-tough graphene paper is fabricated by vacuum filtration of functionalized graphenes dispersed in organic solvent. The graphene is functionalized with polycaprolactone (PCL) brushes on the surface by polymerization of caprolactone from functional groups on graphene. The polymer brushes effectively serve as a soft physical crosslinking system for the graphene, thus providing the graphene paper with super-toughness, 3.49 × 10 6 (J m −3 ), which is 5-fold stronger than paper made of unmodified graphene and surpasses the highest previous values reported for graphene oxide and graphene papers. The functionalized graphene paper exhibits excellent capacity as the anode for a lithium ion battery (LIB). The stabilized discharge capacity of the paper is around 450 mA h g −1 at a constant current density of 300 mA g −1 . This value is approximately 2.7-fold higher than that of an anode made of unmodified graphene and is much higher than most of the values reported for LIB anodes made of graphene paper or graphene powder–polymer binder composites.

Oligomeric dual functional antibacterial polycaprolactone

Dual functional antibacterial and biodegradable caprolactone (CL) based oligomers were prepared by ring-opening polymerization of caprolactone using a polyguanidine macroinitiator. Primary amino (–NH2) end-groups of linear poly(hexamethylene guanidine) hydrochloride (PHMG) acted as initiating sites for caprolactone polymerization leading to block copolymers which combine the antibacterial properties of PHMG with degradability provided by PCL. The block structure of the material was confirmed with 2D NMR and MALDI-ToF-MS. Furthermore, the material exhibited temperature dependent solubility (upper critical solution temperature) in polar solvents such as methanol. The oligomers showed high antibacterial activity (reduction of bacterial cells was more than 3 orders of magnitude) even at short incubation times depending on the concentration and PHMG : PCL ratio while maintaining enzymatic degradability and biocompatibility.