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Lewis pair (LP) catalysis is a powerful system for polymerizing lactone monomers into cyclic polymers. However, current work reveals that the DBU-ZnEt2 LP-catalytic system leads to the formation of linear polymers via an anionic initiation pathway.

Generation of renewable polymers is a long-standing goal toward reaching a more sustainable society, but building blocks in biomass can be incompatible with desired polymerization type, hampering the full implementation potential of biomaterials. Herein, we show how conceptually simple oxidative transformations can be used to unlock the inherent reactivity of terpene synthons in generating polyesters by two different mechanisms starting from the same α-pinene substrate. In the first pathway, α-pinene was oxidized into the bicyclic verbanone-based lactone and subsequently polymerized into star-shaped polymers via ring-opening polymerization, resulting in a biobased semicrystalline polyester with tunable glass transition and melting temperatures. In a second pathway, polyesters were synthesized via polycondensation, utilizing the diol 1-(1′-hydroxyethyl)-3-(2′-hydroxy-ethyl)-2,2-dimethylcyclobutane (HHDC) synthesized by oxidative cleavage of the double bond of α-pinene, together with unsaturated biobased diesters such as dimethyl maleate (DMM) and dimethyl itaconate (DMI). The resulting families of terpene-based polyesters were thereafter successfully cross-linked by either transetherification, utilizing the terminal hydroxyl groups of the synthesized verbanone-based materials, or by UV irradiation, utilizing the unsaturation provided by the DMM or DMI moieties within the HHDC-based copolymers. This work highlights the potential to apply an oxidative toolbox to valorize inert terpene metabolites enabling generation of biosourced polyesters and coatings thereof by complementary mechanisms.

To address the increasing demand for biobased materials, lignin-derived ferulic acid (FA) is a promising candidate. In this study, an FA-derived styrene-like monomer, referred to as 2-methoxy-4-vinylphenol (MVP), was used as the platform to prepare functional monomers for radical polymerizations. Hydrophobic biobased monomers derived from MVP were polymerized via solution and emulsion polymerization resulting in homo- and copolymers with a wide range of thermal properties, thus showcasing their potential in thermoplastic applications. Moreover, divinylbenzene (DVB)-like monomers were prepared from MVP by varying the aliphatic chain length between the MVP units. These biobased monomers were thermally crosslinked with thiol-bearing reagents to produce thermosets with different crosslinking densities in order to demonstrate their thermosetting applications. The results of this study expand the scope of MVP-derived monomers that can be used in free-radical polymerizations toward the preparation of new biobased and functional materials from lignin.

Chemical recycling of poly(L-lactic acid) to the cyclic monomer L-lactide is hampered by low selectivity and by epimerization and elimination reactions, impeding its use on a large scale. The high number of side reactions originates from the high ceiling temperature (T

Chemical wood cellulose fiber modification is performed with the purpose to improve compatibility and induce nanofibrillation of the fibers during melt compounding of thermoplastic biocomposites. C...

To extend the use of naturally occurring substituted δ-lactones within the polymer field, their commonly low ceiling temperature and thereby challenging equilibrium behavior needs to be addressed. A synthetic strategy to control the polymerization thermodynamics was therefore developed. This was achieved by copolymerizing δ-decalactone (δDL) with either e-decalactone (eDL) or e-caprolactone (eCL) at room temperature (RT), with diphenyl phosphate (DPP) as catalyst. The thermodynamic stability of PδDL-co-eDL and PδDL-co-eCL increased with increased comonomer ratio in the feed, to 10% and 30% monomeric δDL, respectively, at 110 °C. This is in contrast to the PδDL homopolymer, which under the same conditions depolymerized to 70% monomeric δDL at equilibrium. The copolymers’ macromolecular structure, originating from the copolymerization kinetics, was found to be the crucial factor to mitigate δDLs equilibrium behavior. To close the loop, designing materials for a circular economy, the recycling of PδDL-co-eDL was demonstrated, by reaction with benzyl alcohol (BnOH) as an external nucleophile, leading to cyclic monomers or dimers with BnOH at high yield.

Cellulose nanofiber (CNF) as a bio-based reinforcement has attracted tremendous interests in engineering polymer composites. This study developed a sustainable approach to reinforce polyamide-6 or nylon-6 (PA6) with CNFs through solvent casting in formic acid/water mixtures. The methodology provides an energy-efficient pathway towards well-dispersed high-CNF content PA6 biocomposites. Nanocomposite formulations up to 50 wt.% of CNFs were prepared, and excellent improvements in the tensile properties were observed, with an increase in the elastic modulus from 1.5 to 4.2 GPa, and in the tensile strength from 46.3 to 124 MPa. The experimental tensile values were compared with the analytical values obtained by micromechanical models. Fractured surfaces were observed using scanning electron microscopy to examine the interface morphology. FTIR revealed strong hydrogen bonding at the interface, and the thermal parameters were determined using TGA and DSC, where the nanocomposites’ crystallinity tended to reduce with the increase in the CNF content. In addition, nanocomposites showed good thermomechanical stability for all formulations. Overall, this work provides a facile fabrication pathway for high-CNF content nanocomposites of PA6 for high-performance and advanced material applications This research was funded by the Biocomposites Program within the Knut and Alice Wallenberg Foundation (Sweden), a UdG grant (IFUdG 2017), Spain, and a three-month research grant from KTH (C2019-1106), Sweden. Support from the Spanish Ministry of Science, Innovation and Universities (RTI 2018-102070-B-C22) is also acknowledged

Transforming biomass derived components to materials with controlled and predictable properties is a major challenge. Current work describes the controlled synthesis of starcopolymers with functional and degradable arms from the Lignoboost® process. Macromolecular control is achieved by combining lignin fractionation and characterization with ring-opening copolymerization (ROCP). The cyclic monomers used are e-caprolactone (eCL) and a functional carbonate monomer, 2-allyloxymethyl-2-ethyltrimethylene carbonate (AOMEC). The synthesis is performed at ambient temperature, under bulk conditions, in an open flask, and the graft composition and allyl functionality distribution are controlled by the copolymerization kinetics. Emphasis is placed on understanding the initiation efficiency, structural changes to the lignin backbone and the final macromolecular architecture. The present approach provides a green, scalable and cost effective protocol to create well-defined functional macromolecules from technical lignins.

Recyclable biocomposites based on degradable polymer systems and cellulosic plant fibers are attractive in a sustainable society, because of enhanced polymer properties and also from an end-of-life perspective. Improved understanding is required for how the degradable polymer matrix is affected during compounding in addition to effects from the cellulosic fiber structure and its chemical nature. This work reveals that a poly(ε-caprolactone) matrix undergoes localized, heterogeneous polymer degradation in the fiber-matrix interphase region during melt-compounding. The extent of localized degradation correlates with the initial moisture content in the wood cellulose fiber, where moisture content is controlled by different fiber modification methods by PCL-grafting. As an effect, high moisture content results in a destabilized and degraded fiber-matrix interphase. This was found through careful analysis of how the polymer population changed after compounding, using two different methods: molar mass distribution from SEC and end-group concentration from NMR. The results are important not only with regard to fiber/matrix interface compatibility but also to understand fiber modification for improved biocomposites recycling.

Prekarisering har indtil for nyligt overvejende været forbundet med betingelser for kortuddannede og i en europæisk kontekst primært lokaliseret til sydeuropæiske lande. Men analyser peger på, at prekarisering har bredt sig til nordeuropæiske lande og til mange sektorer og faggrupper, herunder akademikere. Der er imidlertid kun i begrænset omfang forsket i prekarisering og akademisk arbejde, ligesom der i mindre omfang er forsket i de subjektive konsekvenser af prekariseringen. Artiklen fremlægger resultater fra et forskningsprojekt med empirisk omdrejningspunkt i, hvordan prekarisering opleves og håndteres af akademikere, der lever med midlertidige og usikre ansættelsesforhold .

The present work explores different cyclic allylic carbonates as a potential class of allylcarbamate precursors. The 5-membered carbonate formed a carbamate with very good thermal and pH stability, which could be cleanly deprotected in aqueous solution, in just 30 min with 2 mol% Pd(OAc)2 as catalyst. The polar nature of the installed motif made it possible to deprotect highly unpolar substrates in water as solvent.

The present work shows that it is possible to ring-open cyclic carbonates with unprotected amino acids in water. Fine tuning of the reaction parameters made it possible to suppress the degree of hydrolysis in relation to aminolysis. This enabled the synthesis of functionally dense carbamates containing alkenes, carboxylic acids, alcohols and thiols after short reaction times at room temperature. When Glycine was used as the nucleophile in the ring-opening with four different five membered cyclic carbonates, containing a plethora of functional groups, the corresponding carbamates could be obtained in excellent yields (>90%) without the need for any further purification. Furthermore, the orthogonality of the transformation was explored through ring-opening of divinylenecarbonate with unprotected amino acids equipped with nucleophilic side chains, such as serine and cysteine. In these cases the reaction selectively produced the desired carbamate, in 70 and 50% yield respectively. The synthetic design provides an inexpensive and scalable protocol towards highly functionalized building blocks that are envisioned to find applications in both the small and macromolecular arena.

Senest siden 1980erne har neo-liberalistiske diskurser i de vestlige sen-kapitalistiske samfund præsenteret et optimistisk billede af ny subjektivitet i arbejdet, præget af autonomi og udvikling. Men et historisk materialistisk blik giver et andet billede. Globaliseringen rummer både gamle og nye betingelser i det samfundsmæssige arbejde; denne artikel skitserer i teseform, hvordan nye former for magt, kooperation og sociale relationer i arbejdet ’overlejrer’ de gamle. Vi ser tendenser til en ny ’dynamisering af subjektiviteten’, hvor subjektive ressourcer aktiveres - samtidig med nye belastninger, disciplinering og forsvar. Som bagside ser vi ændrede konflikt- og lideformer, men også (søgen efter) nye former for modstand, kollektivitet og selvstændighed.

Herein, we report on the facile synthesis of a heterogeneous copper nanocatalyst and its combination with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) for the aerobic oxidation of alcohols to their corresponding carbonyl compounds. This low cost copper nanocatalyst was found to exhibit excellent recyclability, making it a highly attractive catalytic system from an economical and environmental point of view. Extensive characterization of the catalyst by a number of techniques revealed that it was comprised of well-dispersed Cu(I/II) nanoparticles with an average size of around 6nm. Version of record online: 14 November 2017

Herein we report the synthesis of mesoporous ruthenium oxide (MP-RuO2) using a template-based approach. The catalytic efficiency of the prepared MP-RuO2 was compared to commercially available ruthenium oxide nanoparticles (C-RuO2) as heterogeneous catalysts for water oxidation. The results demonstrated superior performance of MP-RuO2 for oxygen evolution compared to the C-RuO2 with respect to recyclability, amount of generated oxygen, and stability over several catalytic runs.

Cellulose nanofibrils (CNFs) show high modulus and strength and are already used in industrial applications. Mechanical properties of neat CNF films or CNF-polymer matrix nanocomposites are usually much better than for polymer matrix composite films reinforced by clay, graphene, graphene oxide, or carbon nanotubes. In order to obtain small CNF diameter and colloidal stability, chemical modification has so far been necessary, but this increases cost and reduces eco-friendly attributes. In this study, an unmodified holocellulose CNF (Holo-CNF) with small diameter is obtained from mildly peracetic acid delignified wood fibers. CNF is readily defibrillated by low-energy kitchen blender processing. The hemicellulose coating on individual fibrils in the wood plant cell wall is largely preserved in Holo-CNF. This "native" CNF shows well-preserved native fibril structure in terms of length (∼2.1 μm), diameter (5 nm), high crystallinity, high cellulose molar mass, electronegative charge, and limited mechanical processing damage. The hemicellulose coating contributes mechanical properties and high optical transmittance for CNF nanopaper, which can otherwise only be achieved with chemically modified CNFs. The CNF nanopaper shows superior mechanical properties with a Young's modulus of 21 GPa and an ultimate strength of 320 MPa. Moreover, hemicellulose imparts recyclability from the dried state. Altogether, this native CNF represents a class of colloidally stable, eco-friendly, low-cost CNF of small diameter for large-scale applications of nanopaper and nanomaterials.

Chemical modification of wood cellulose fibers is important for tailored wood-polymer interfaces, reduced moisture sorption, and novel grades of chemical wood pulp. The present study shows how the reaction solvent system influences hydroxyl accessibility during chemical fiber modification. Surface initiated ring-opening polymerization of ε-caprolactone from wood cellulose fibers was investigated in a wide range of solvent systems. The hydrogen bond donor strength of the solvent increased graft density and the amount of grafted polycaprolactone (PCL) on the fiber surface, and on nanoscale fibrils inside the fiber. Specifically, the reaction system with acetic acid as a new, green solvent for cellulose grafting increased graft density 24 times compared to bulk polymerization conditions. The results show relationships between solvent properties, hydroxyl accessibility, and grafting results in cellulosic plant fibers. The study clarifies the opportunities provided by controlling the interior of the cellulosic plant fiber cell wall during chemical modification so that the fiber becomes a swollen cellulose nanofibril gel.

Full control over the ceiling temperature (Tc) enables a selective transition between the monomeric and polymeric state. This is exemplified by the conversion of the monomer 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC) to poly(AOMEC) and back to AOMEC within 10 h by controlling the reaction from conditions that favor ring-opening polymerization (Tc > T0) (where T0 is the reaction temperature) to conditions that favor ring-closing depolymerization (Tc < T0). The ring-closing depolymerization (RCDP) mirrors the polymerization behavior with a clear relation between the monomer concentration and the molecular weight of the polymer, indicating that RCDP occurs at the chain end. The Tc of the polymerization system is highly dependent on the nature of the solvent, for example, in toluene, the Tc of AOMEC is 234 °C and in acetonitrile Tc = 142 °C at the same initial monomer concentration of 2 M. The control over the monomer to polymer equilibrium sets new standards for the selective degradation of poly...

Degradable polymers based on α-hydroxy acids and α-amino acids constitutes a potent class of biomaterials, combining high hydrolyzability with structural features that mimics peptides. Driven by the design criteria to construct isolated α-amino acid units along a main polylactide chain, a copolymer system was developed based on two monomers with distinctly different equilibrium behaviors. This was uncovered by detailed understanding on the kinetic and thermodynamic polymerizability of 3S,6S-dimethylmorpholine-2,5-dione (DMMD) and L-lactide (LLA) at low reaction temperatures. Under Bronsted base-promoted ring-opening copolymerization (ROCOP) conditions, the equilibrium nature of the copolymerization was shown susceptible to changes in the system, such as catalyst basicity, solvent polarity and initial monomer concentrations. Subsequently, high equilibrium conversions of both monomers with control over molecular weight and dispersity could be achieved within short reaction times by modulation of these factors. Thermodynamic elucidations of the copolymerization system revealed that DMMD behaved as an unstrained monomer with a large propagation barrier, favored by an increase in polymerization temperature. Ultimately, the high propagation barrier of DMMD in the system resulted in a kinetically controlled mechanism with the formation of completely isolated units of DMMD along the polylactide backbone. These results extend current ROCOP strategies of morpholine-2,5-diones and cyclic esters to a mild and selective copolymerization platform for the construction of sequence-controlled α-amino acid decorated polyesters for medical applications.

The current work explores the sodium hydride mediated polycondensation of aliphatic diols with diethyl carbonate to produce both aliphatic polycarbonates and cyclic carbonate monomers. The lengths of the diol dictate the outcome of the reaction; for ethylene glycol and seven other 1,3-diols with a wide array of substitution patterns, the corresponding 5-membered and 6-membered cyclic carbonates were synthesized in excellent yield (70-90%) on a 100 gram scale. Diols with longer alkyl chains, under the same conditions, yielded polycarbonates with an

The employment of a monomer-specific “on/off switch” was used to synthesize a nine-block copolymer with a predetermined molecular weight and narrow distribution (Đ = 1.26) in only 2.5 h. The monomers consisted of a six-membered cyclic carbonate (i.e., 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC)) and ε-caprolactone (εCL), which were catalyzed by 1,5,7-triazabicyclo[4.4.0]-dec-5-ene (TBD). The dependence of polymerization rate with temperature was different for the two monomers. Under similar reaction conditions, the ratio of the apparent rate constant of AOMEC and εCL [kpapp(AOMEC)/kpapp(εCL)] changes from 400 at T = −40 °C to 50 at T = 30 °C and 10 at T = 100 °C. Therefore, by decreasing the copolymerization temperature from 30 °C to −40 °C, the conversion of εCL can be switched “off”, and by increasing the temperature to 30 °C, the conversion of εCL can be switched “on” again. The addition of AOMEC at T = −40 °C results in the formation of a pure carbonate block. The cyclic addition of AOMEC to a solution of εCL along with a simultaneous temperature change leads to the formation of multiblock copolymers. This result provides a new straightforward synthetic route to degradable multiblock copolymers, yielding new interesting materials with endless structural possibilities.

The treatment of bone defects is facing the situation of lacking donations for autotransplantation. As a valid approach, scaffold-based tissue engineering combines the construction of well-defined porous scaffolds with advanced cell culturing technology to guide tissue regeneration. The role for the scaffold is to provide a suitable environment with a sufficient mechanical stiffness, supports for cell attachment, migration, nutrients and metabolite transport and space for cell remodeling and tissue regeneration. The random copolymers poly(L-lactide-co-ɛ-caprolactone) (poly(LLA-co-CL)) and poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) have been successfully incorporated into 3D porous scaffolds to induce specific interactions with cells and direct osteogenic cell differentiation. In this thesis, these scaffolds have been modified in chemical and physical ways to map and understand requirements for bone regeneration. Scaffold functionalities and properties, such as hydrophilicity, stiffness, size/shape, and reproducibility, were studied. The hydrophilicity was varied by adding 3–20 % (w/w) Tween 80 to poly(LLA-co-CL) and poly(LLA-co-DXO) respectively, which resulted in contact angles from 35° to 15°. With 3 % Tween 80, the resultant mechanical and thermal properties were similar to pristine polymer materials. Tween 80 did not significantly influence cell attachment or proliferation but did stimulate the mRNA expression of osteogenetic markers. The surface functionality and mechanical properties were altered by introducing nanodiamond particles (n-DP) into poly(LLA-co-CL) scaffolds by means of surface physisorption or hybrid blending. Scaffold with n-DP physisorbed showed improved cell attachment, differentiation, and bone reformation. Hybrid n-DP/poly(LLA-co-CL) composites were obtained by direct blending of polylactide modified n-DP (n-DP-PLA) with poly(LLA-coCL). The n-DP-PLA was prepared by sodium hydride-mediated anionic polymerization using n-DP as the initiator. Prepared n-DP-PLA could be dispersed homogenously in organic solvents and blended with poly(LLA-coCL) solution. The n-DP-PLA particles were homogenously distributed in the composite material, which significantly improved mechanical properties. For comparison, the addition of benzoquinone-modified n-DP (n-DP-BQ) did not reinforce poly(LLA-co-CL). This indicated the importance of specific surface grafting, which determined different particle-polymer interactions. For the treatment of critical size defects, a large porous poly(LLA-co-CL) scaffold (12.5 mm diameter × 25 mm thickness) was developed and produced by molding and salt-leaching methods. The large porous scaffolds were evaluated in a scaffold-customized perfusion-based bioreactor system. It was obvious that the scaffold could support improved cell distribution and support the stimulation of human mesenchymal stem cell (hMSC) especially with dynamic flow in a bioreactor. To improve the scaffolding technique, a three-dimensional fiber deposition (3DF) technique was employed to build layer-based scaffolds. Poly(LLA-coCL) scaffolds produced by the 3DF method showed enhanced mechanical properties and a homogeneous distribution of human osteoblasts (hOBs) in the scaffolds. Although poly(LLA-co-CL) was thermally degraded, the degradation did not influence the scaffold mechanical properties. Based on the computerized design, a 3DF scaffold of amorphous copolymer poly(LLAco-CL) provides high-precision control and reproducibility. In summary, the design of porous scaffolds is one of the essential factors in tissue engineering as to mimicking the intrinsic extracellular environment. For bone tissue engineering, an optimized scaffold can maintain a contact angle greater than 35 degrees. Pristine or modified n-DP, introduced as an additive by surface physisorption or direct blending, can improve scaffold mechanical properties and cell response. Various sizes of scaffolds can be easily produced by a mold-mediated salt-leaching method. However, when 100 % reproducibility is required, the 3DF method can be used to create customizable scaffolds.

We have designed a pathway for controlling the critical micelle concentration and micelle size of polyester-based systems. This was achieved by creating an array of different copolymers with semicrystalline or amorphous hydrophobic blocks. The hydrophobic block was constructed through ring-opening polymerization of ε-caprolactone, L-lactide, and ε-decalactone, either as homopolymers or random copolymers, using PEG as both the initiator and the hydrophilic block. Micelles formed with amorphous cores exhibited considerably higher critical micelle concentrations than those with semicrystalline cores. Micelles with amorphous cores also became larger in size with an increased molecular weight of the hydrophobic bock, in contrast to micelles with semicrystalline cores, which displayed the opposite behavior. Hence, core crystallinity was found to be a potent tool for tailoring micelle properties and thereby facilitating the optimization of drug delivery systems. The introduction of PEG-PεDL also proved to be a valuable asset in the tuning of micelle properties.

The renewable monomer ε-decalactone is an excellent partner to L-lactide, where their copolymers overcome inherent drawbacks of polylactide, such as low thermal stability and brittleness. ε-Decalactone is a seven-membered lactone that was successfully polymerized with Sn(Oct)(2) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene into both an amorphous homopolymer and copolymers with high molecular weight, low dispersity, and predicted macromolecular architecture. The thermoresilient nature of ε-decalactone is reflected in a high polymerization ceiling temperature and increased thermal stability for the prepared copolymers. The high ceiling temperature enables easy modulation of the polymerization rate via temperature while maintaining architectural control. The apparent rate constant was increased 15-fold when the temperature was increased from 110 to 150 °C. Copolymers of L-lactide and ε-decalactone, either with the latter as a central block in triblock polymers or with randomly positioned monomers, exhibited exceptionally tough material characteristics. The triblock copolymer had an elongation-at-break 250 times greater than that of pure poly(L-lactide). The toughness of the copolymers is attributed to the flexible nature of the polymer derived from the monomer ε-decalactone and to the segment immiscibility. These properties result in phase separation to soft and hard domains, which provides the basis for the elastomeric behavior.

The need for polymers for high-end applications, coupled with the desire to mimic nature’s macromolecular machinery fuels the development of innovative synthetic strategies every year. The recently acquired macromolecular-synthetic tools increase the precision and enable the synthesis of polymers with high control and low dispersity. However, regardless of the specificity, the polymerization behavior is highly dependent on the monomeric structure. This is particularly true for the ring-opening polymerization of lactones, in which the ring size and degree of substitution highly influence the polymer formation properties. In other words, there are two important factors to contemplate when considering the particular polymerization behavior of a specific monomer: catalytic specificity and thermodynamic equilibrium behavior. This perspective focuses on the latter and undertakes a holistic approach among the different lactones with regard to the equilibrium thermodynamic polymerization behavior and its relation to polymer synthesis. This is summarized in a monomeric overview diagram that acts as a presynthetic directional cursor for synthesizing highly specific macromolecules; the means by which monomer equilibrium conversion relates to starting temperature, concentration, ring size, degree of substitution, and its implications for polymerization behavior are discussed. These discussions emphasize the importance of considering not only the catalytic system but also the monomer size and structure relations to thermodynamic equilibrium behavior. The thermodynamic equilibrium behavior relation with a monomer structure offers an additional layer of complexity to our molecular toolbox and, if it is harnessed accordingly, enables a powerful route to both monomer formation and intentional macromolecular design.

Full control over the ceiling temperature (Tc) enables a selective transition between the monomeric and polymeric state. This is exemplified by the conversion of the monomer 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC) to poly(AOMEC) and back to AOMEC within 10 h by controlling the reaction from conditions that favor ring-opening polymerization (Tc > T0) (where T0 is the reaction temperature) to conditions that favor ring-closing depolymerization (Tc < T0). The ring-closing depolymerization (RCDP) mirrors the polymerization behavior with a clear relation between the monomer concentration and the molecular weight of the polymer, indicating that RCDP occurs at the chain end. The Tc of the polymerization system is highly dependent on the nature of the solvent, for example, in toluene, the Tc of AOMEC is 234 °C and in acetonitrile Tc = 142 °C at the same initial monomer concentration of 2 M. The control over the monomer to polymer equilibrium sets new standards for the selective degradation of polymers, the controlled release of active components, monomer synthesis and material recycling. In particular, the knowledge of the monomer to polymer equilibrium of polymers in solution under selected environmental conditions is of paramount importance for in vivo applications, where the polymer chain is subjected to both high dilution and a high polarity medium in the presence of catalysts, that is, very different conditions from which the polymer was formed.

This article is about meaning and sensemaking in work – as a precondition for employees’ participation and commitment in changing and improving their work. Results from a Danish research project (the BEST project) are presented. Fourteen companies and institutions tried to improve their psychosocial work environment, but many of them failed; even seeing this worsen. Nevertheless, employees everywhere expressed a surprising (desire for) involvement in work – although often frustrated and conflictual. This may indicate a great under-utilised potential for improving work and working conditions. After presenting a specific concept of the work task, a theoretical model is outlined – proposing the work task as pivotal for employees’ creation (or loss) of meaning and sense in their work. This is of special importance when it comes to processes of change: employees’ participation and commitment to change depends on the meaning of the goal. This is crucial when trying to improve the psychosocial work environment. Finally, some consequenses for practise are suggested, as is a wider perspective of democratizing work as a condition for a sustainable psychosocial work environment.

Ring-closing depolymerization is demonstrated to be a powerful synthetic methodology for the formation of six-membered functional aliphatic carbonate monomers, providing a rapid, straightforward, inexpensive, and green route for obtaining six-membered functional aliphatic carbonate monomers at a scale greater than 100 g. The utility of this technique was observed via the synthesis of the allyloxy-functionalized six-membered cyclic carbonate monomer 2-allyloxymethyl-2-ethyltrimethylene carbonate (AOMEC). The synthesis was performed in a one-pot bulk reaction, starting from trimethylolpropane allyl ether, diethyl carbonate, and NaH, resulting in a final AOMEC yield of 63%. The synthetic methodology is based upon the reversible nature of this class of polymers. The anionic environment produced by NaH was observed to be sufficient to mediate the monomer equilibrium concentration; thus, an additional catalyst is not required to induce depolymerization. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) was demonstrated...

Utilizing a-bromo-g-butyrolactone (aBrgBL) as a comonomer with 3-caprolactone (3CL) or L-lactide (LLA)produces copolymers with active and available grafting sites, e.g., for SET-LRP, where the choice of thegrafting monomers is limited only by one's imagination. This was deduced by utilizing a wide range ofdifferent acrylates of varying polarities and was realized with the aid of a fluorinated alcohol, 2,2,2-trifluoroethanol, which acts as a universal solvent for both the hydrophobic macroinitiators and thegrafting monomers. Using aBrgBL successfully provides a simple route to merge the two polymerizationmethodologies, ROP and SET-LRP. aBrgBL inherently meets all of the prerequisites to act as a platformmonomer for the synthesis of functional aliphatic polyesters, i.e., it is inexpensive, available, and able toform isolated grafting sites along the polymer chain. The copolymerization of aBrgBL together with twoof the most commonly used cyclic ester monomers, 3-CL and LLA, proceeds with a high degree ofcontrol and a linear relationship between the feed ratio of aBrgBL and its composition in the copolymer.The formation of isolated units of aBrgBL in the copolymer is visualized by the reactivity ratios of thecopolymerization reactions and confirmed by 13C-NMR spectroscopy. The incorporation of isolatedaBrgBL is the feature that makes this class of copolymers unique, and it can be considered to provide aroute to the “perfect graft copolymer” with a degradable backbone. QC 20140627

After presenting different conceptions of work politics in industrial sociology and sociology of organization, the authors argue that changes in work and technology, and hence the politics of work, may be better comprehended through a concept of the social constitution of the company. Subsequently, this concept is used as a theoretical and methodological basis for an in-depth case study of the processes of social change connected with the introduction of semi-autonomous working groups in a Danish electronic manufacturing plant. It is shown that the historically developed norms and culture of the organization - referred to here as the social constitution of the company - contribute to the creation of profound, ambivalent attitudes among management as well as workers towards more fundamental changes of work content and organization. Finally, the implications for strategic management for the development of work at the company level are discussed.

The uropathogenic Escherichia coli strain 536 (O6:K15: H31) carries two large chromosomal pathogenicity islands (Pais). Both Pais are flanked by tRNA genes. Spontaneous deletion of Pai II results in truncation of the leuX tRNALeu5 gene. This tRNA is required for the expression of type 1 fimbriae (Fim) and other virulence factors. Transcription of fimA, encoding the major type 1 fimbrial subunit is controlled by an invertable DNA switch. The inversion is catalysed by two recombinases, FimB and FimE. FimB is able to turn the switch on, FimE only off. The fimB gene of strain 536 contains five TTG codons recognized by tRNALeu5, fimE contains only two. It was proposed that turning on the fim switch requires efficient translation of FimB, in turn requiring tRNALeu5. Strains in which the TTG codons in fimB were replaced with CTG codons at the wild-type locus were able to produce type 1 fimbriae in the absence of leuX. fimB transcription was influenced by the presence of leuX, but only slightly affected by the presence or absence of leuX codons in fimB. FimB translation was significantly higher from codon-replaced fimB genes than that of wild-type fimB genes in various strain backgrounds. The fim switch was shown to be switched off in leuX − derivatives of E. coli 536, but could be found in the on position when the codon-altered fimB gene was exchanged into the chromosome of these strains. From these data, it is apparent that tRNALeu5 is required for efficient translation of FimB, in turn, leading to type 1 fimbrial expression.

Main-chain-functionalized poly(L-lactide) (PLLA) with pendant unsaturations was synthesized through a one-pot postpolymerization procedure with the PLLA homopolymer as the starting material. The material was functionalized through a-hydrogen abstraction by a sterically hindered strong base, lithium diisopropylamide, followed by the addition of an acid chloride. Two different acid chlorides were examined, lauroyl chloride as a concept electrophile and oleoyl chloride to provide the pendant unsaturations. The semisolvated system, together with branching reactions from the alpha position of the acid chloride, yielded a high molar amount of the incorporated reactant in the material. The unsaturations were preserved under the chosen conditions and the material exhibited surfactant-like properties in blends with oleic acid and PLLA.

Recent research on unskilled industrial work suggests that workers' orientations to work are complex and ambivalent implying defence mechanisms, resistance and (latent) interest in the work and its change. This notion is discussed in the first part of the article and it represents the theoretical starting point for the project presented in the second part. In a current action research project, called 'Industry and Happiness', an egalitarian co-operation between unskilled workers and researchers has been developed. Through a utopian working method the workers have developed autonomous learning processes. On the basis of their own experiences they have produced visions of a democratic industry viewed as part of a better life. The workers and researchers aim at a practical social experiment in order to try out the visions, step by step, in a future self-governed fishing industry.

Artiklen tager udgangspunkt i et traditionelt dilemma i arbejdspsykologiens mainstream mellem på den ene side et HUMANITÆRT engagement og på den anden side TILPASNING til UDEMOKRATISKE forhold. Dette dilemma ændrer udseende op gennem den nyere historie. I artiklen forfølges dette dilemma med UD VIK LINGS-forståelsen som omdrejningspunkt, kulminerende i det nye ‘vidensarbejde’. De dominerende udviklingsforståelser kritiseres og relateres til den materielle og organisatoriske udvikling i arbejde og hverdagsliv, med dets modsigelser mellem magt, disciplinering og modstand. Her får psykologien let en INSTRUMENTEL rolle, ikke mindst dér hvor den taler allermest ‘SUBJEKTIVT’. DEMOKRATISERING af arbejdet kræver andre målestokke end ekspertlogikker og abstrakt vækst. I artiklen henvises til forfatternes egne projekterfaringer med ‘frirum’ og alternative demokratiske samarbejdsformer mellem almindelige mennesker og eksperter. Her er begreberne erfaring, livssammenhæng og social fantasi centrale.

I denne artikel belyses samspillet mellem 'udvikling af de menneskelige ressourcer' og de sociale relationer i virksomhederne. Formålet er at undersøge, hvad udviklingen betyder for arbejdernes indbyrdes solidaritet og deres relation til lederne og virksomheden. Afslutningsvis diskuteres udviklingens betydning for den danske fagbevægelse.

Det tayloriserede industriarbejde er under forandring; men forandringerne er vanskelige og modsætningsfulde. Hvordan medvirker arbejderne i disse processer? To projekter om 'humanisering af arbejdet' belyser dette - hver på sin måde. På den ene side ser vi arbejdernes modstand og forsvar, på den anden side deres engagement og visioner. Modsigelserne i arbejdernes reaktioner hænger sammen med magtforhold og indre modsigelser i arbejdserfaringerne. Artiklen diskuterer, hvordan forskellige forsøgsbetingelser og udviklingsstrategier lader forskellige sider af arbejdernes erfaringer og interesser komme til udtryk. Og hvordan demokratiske udviklingsbetingelser kan rumme muligheder for radikale fornyelser.