The science behind repeating units

There are few books that provide a good introduction to polymer chemistry; this new text aims to do just that for an undergraduate audience and beyond

David Sherrington commemorative issue

This themed issue of Polymer Chemistry was commissioned following the passing, in October 2014, of Professor David Colin Sherrington, FRS. It was commissioned as a dedication to the memory of a world-class polymer chemist of international renown, as well as a celebration of a subject area that was very close to Dave's heart and upon which he founded his career and made his name. It is entirely appropriate that this collection of papers is published in a leading international journal that bears the name of the subject field with which Dave's name is synonymous and to which he contributed so much – Polymer Chemistry – and that this collection be published in the UK by his own professional chemical society, the Royal Society of Chemistry

Organic farming: technology transfer (Environmental impact and soil fertility) (OF0405)

This project covered two separate activities, but both were examples of technology transfer, relating to organic farming: 1. Developing a science-based report, which covered an assessment of the environmental impacts of organic farming. Defra’s Action Plan to Develop Organic Food and Farming included as Annexe 3 an assessment of the environmental impacts of organic farming. This paper was prepared by a Subgroup of the Action Plan for Organic Farming. Its purpose was to summarise the Subgroup’s views of the likely comparative effects of organic and conventional farming on the environment. However, to be robust and defensible, the assessment needs to be supported by scientific data. Although the report was based on such an assessment, the scientific data were not summarised and this needed to be done. The objective of this part of the project was therefore to collate and publish on the Defra website the evidence that underpinned the overall conclusions. 2. Preparation of a booklet to provide guidelines for managing soil fertility in organic farming. Organic farming aims to create an economically and environmentally sustainable agriculture, with the emphasis placed on self-sustaining biological systems, rather than external inputs. Building soil fertility is central to this ethos. ‘Soil fertility’ can be considered as a measure of the soil’s ability to sustain satisfactory crop growth, both in the short- and longer-term, and it is determined by a set of interactions between the soil’s physical environment, chemical environment and biological activity. The aim of recent Defra-funded projects has been, therefore, to provide a better scientific understanding of ‘soil fertility’ under organic farming, in line with Defra’s policy objective of greater technical support to organic farming. The aim here was to prepare a booklet based on the findings of Defra-funded project OF0164 ‘Soil fertility in organically farmed soils’

Residential school placements for children and young people with intellectual disabilities: their use and implications for adult social care

Out of area residential placements are associated with a range of poor outcomes for adults with intellectual disabilities and behaviours that challenge. In recent years there has been an increased drive to reduce such placements at as early a stage as possible. In this context the current review collates research and policy regarding use of residential schools for children and young people with intellectual disabilities and transition from these settings to adult services. The review highlights that relatively little is known about both use of, and transition from, residential schooling for children and young people with intellectual disabilities in the UK. Thirteen articles are identified: 7 examining the child or families’ experiences before placement, 4 examining outcomes during the placement, and 4 examining the process of transitioning from the placement and longer term outcomes. The methodological quality of articles was often limited. A lack of control groups, independent samples, or adequate sample sizes was particularly notable. Results are discussed in relation to factors that lead to a child’s placement in a residential school, children and families’ experiences of the placement, and outcomes following placement, including the transition process. A number of research priorities are highlighted based on gaps in the literature. Examples of alternative forms of support from clinical practice are provided, with recognition that a multi-element model is likely to be needed to provide high quality support to this group of young people

Reflux precipitation polymerization : a new synthetic insight in molecular imprinting at high temperature

Synthesis of uniform molecularly imprinted polymer (MIP) microspheres (MSs) using distillation precipitation polymerization (DPP) at high temperature has attracted great interest in the field of molecular imprinting. However,there were still some shortcomings in this method. In this work, to create uniform MIP MSs in a short time and to demonstrate the effects of high temperature on imprinting performance, a new precipitation polymerization method (reflux precipitation polymerization, RPP) was used for the first time to fabricate MIP MSs in this study. The SEM images of the polymeric MSs indicate the presence of template molecules could improve the particle morphology and size uniformity. The specific molecular recognition of the monodispersed MIP MSs was confirmed by fluorescence measurement and HPLC-UV analysis. The binding behavior of the MIP MSs was simulated using the heterogeneous Freundlich isotherm, which shows that the MIP MSs produced by the RPP possess compatible selectivity in comparison with those by traditional PP method. It is noted that, for the first time, we demonstrated that molecular imprinting at high temperature was only successful when electrostatic interactions played important roles in the imprinting process

A deterministic method for particle sorting by dynamic acoustic fields

This paper investigates the dynamic acoustic sorting method from a theoretical perspective. Analytical equations of motion and numerical simulations have been used to optimize parameters for sorting various particle mixtures. The effect of changes in field parameters as frequency or voltage on efficient sorting has been investigated. Experiments have been carried out to verify theoretical findings

Synthesis of poly(acrylonitrile-co-divinylbenzene-co-vinylbenzyl chloride)-derived hypercrosslinked polymer microspheres and a preliminary evaluation of their potential for the solid-phase capture of pharmaceuticals

Poly[acrylonitrile (AN)‐co‐divinylbenzene (DVB)‐co‐vinylbenzyl chloride (VBC)] terpolymers were synthesized by precipitation polymerization in the form of porous polymer microspheres. The poly(AN‐co‐DVB‐co‐VBC) polymers were then hypercrosslinked, via a Friedel‐Crafts reaction with FeCl3 in nitrobenzene, to provide a significant uplift in the specific surface areas of the polymers. FTIR spectra of the hypercrosslinked poly(AN‐co‐DVB‐co‐VBC)s showed that the chloromethyl groups derived from VBC were consumed by the Friedel‐Crafts reactions, which was consistent with successful hypercrosslinking. Hypercrosslinking installed a number of new, small pores into the polymers, as evidenced by a dramatic increase in the specific surface areas upon hypercrosslinking (from ∼530 to 1080 m2 g−1). The hypercrosslinked polymers are very interesting for a range of applications, not least of all for solid‐phase extraction (SPE) work, where the convenient physical form of the polymers (beaded format), their low mean particle diameters, and narrow particle size distributions, as well as their high specific surface areas and polar character (arising from the AN residues), make them attractive candidates as SPE sorbents. In this regard, in a preliminary study one of the hypercrosslinked polymers was utilized as an SPE sorbent for the capture of the polar pharmaceutical diclofenac from a polar environment

The synthesis and characterisation of porous thioamide-sulfonated-modified poly(acrylonitrile-co-divinylbenzene-80) as a potential sorbent to capture polar analytes

Pharmaceuticals contain biologically active components that can pollute water courses as a result of the excretions from individuals and/or uncontrolled release of residues from chemical plants, and they can pose a hazard to health. Pharmaceutical residues can persist at low concentrations in the environment, and thus may be potentially harmful to aquatic animals and to humans. Controlling and monitoring such residues are therefore a prime interest, for example, a solid-phase extraction uses solid sorbents to purify and preconcentrate the residues prior to their chemical analysis. In the present study, poly (acrylonitrile-co-divinylbenzene-80) sorbents are synthesised by varying the comonomer feed ratios under precipitation polymerisation conditions to deliver a family of porous polymer microspheres. Acrylonitrile confers polar characters onto the sorbents, and the acrylonitrile-derived nitrile groups can be chemically transformed via polymer-analogous reactions into thioamide and sulfonated residues which make the sorbents even more suitable for the capture of polar analytes, including selected pharmaceuticals. The utility of the porous thioamide-sulfonated containing sorbents is demonstrated via the dispersion-solid phase extraction of mefenamic acid from aqueous media; mefenamic acid is an anthranilic acid derivative which is a potent, non-steroidal anti-inflammatory drug which is found in environmental waters at low concentrations

The synthesis and characterisation of porous and monodisperse, chemically modified hypercrosslinked poly(acrylonitrile)-based terpolymer as a sorbent for the adsorption of acidic pharmaceuticals

The synthesis and characterization of porous poly(acrylonitrile(AN)-co-divinylbenzene-80 (DVB-80)-co-vinylbenzylchloride (VBC)) polymers with high specific surface areas and weak anion-exchange character have been successfully researched. The hypercrosslinked (HXL) microspheres were chemically modified with 1,2-ethylenediamine (EDA) to enhance the adsorption selectivity of the HXL materials. The zeta potential of EDA-modified HXL poly(AN-co-DVB-80-co-VBC) revealed that the surface of the modified terpolymer was positively charged. The FT-IR spectra of the chemically modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) showed that the nitrile groups derived from the AN unit were utilised by the presence of diamine groups. The BET-specific surface areas of the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) was 503 m2 g-1; meanwhile, the specific surface area of the HXL terpolymer was 983 m2 g-1. The adsorption isotherm data were well fitted by both the Langmuir and Freundlich models, whereas the adsorption kinetics followed the pseudo-second-order kinetic model. This study confirms that the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) terpolymer is a potential adsorbent for the adsorption of acidic pharmaceuticals

Polymerizable UV absorbers for the UV stabilization of polyesters. I. Design, synthesis and polymerization of a library of UV absorbing monomers

Poly(ethylene terephthalate) (PET) absorbs strongly in the ultraviolet (UV) region of the EM spectrum (Figure 1), and this can lead to photodegradation of the polymer chains and loss of polymer properties. UV stabilizer additives are normally employed to suppress the UV-induced photodegradation of polyester films, especially for those applications where the levels of UV exposure to the polymer film are high, e.g., photovoltaic cells. One limitation concerning the use of UV stabilizers is the loss of additive from the polymers over time by leaching, since UV stabilizers are normally low molar mass organic compounds that can be washed out through weathering actions, and this reduces their effectiveness. One way in which this leaching problem can potentially be circumvented is to lock the UV stabilizers into the polymer chains through covalent bond