Improvement of Impact Toughness of Biodegradable Poly(butylene succinate) by Melt Blending with Sustainable Biobased Glycerol Elastomers

Poly(butylene succinate) (PBS) was melt blended with glycerol based polyesters (PGS) synthesized from pure and technical glycerol aiming to improve the impact strength of PBS. It was found that after addition of 30 wt% PGS to PBS its impact strength was significantly increased by 344% (from 31.9 to 110 J/m) and its elongation at break was maintained at 220%. Infrared spectra of the blends showed the presence of hydroxyl groups from the PGS phase suggesting that hydrogen bonding between the phases could be responsible for a good stress transfer and an efficient toughening in the PBS/PGS blends. Scanning electron microscopy imaging showed a good dispersion of PGS phase into PBS with a PGS particle size of 10 μm and less and no agglomeration. Addition of PGS to PBS was shown to be an effective strategy for improvement of PBS impact resistance without serious detrimental effects on its thermal and rheological properties.     

Preparation and Characterization of Collagens from the Skin of Northern Snakehead (<Emphasis Type="Italic">Channa argus)</Emphasis>

Channa argus, a type of snakehead fish native to China, is a popular food fish in certain Asian countries but is a known destructive invasive species in the US. In this study, the two collagens, i.e. acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC), were obtained from C. argus skin. The yield of ASC was 28.0% and that of PSC was 16.8% on the dry bases. The collagens were identified as the collagen of type I by SDS–PAGE patterns. The Tds were approximately 27.0?°C. Similar ultraviolet spectra of both collagens were observed. Fourier Transform infrared spectra indicated PSC structure had a little change due to the loss of terminal domains by pepsin digestion. The results of XRD proved that the two collagens retained their helical structures. The results suggest that the collagens isolated from C. argus can potentially be alternative sources of vertebrate collagens for use in the food and other industries.     

High Toughness and Fast Crystallization Poly(Lactic Acid)/Polyamide 11/SiO<Subscript>2</Subscript> Composites

A poly(lactic acid) (PLA)/polyamide 11 (PA11)/SiO₂ composite was mixed from PLA, PA11, and nanosilica particles through twin-screw extrusion. The PLA/PA11/SiO₂ composite was evaluated with tensile and Izod impact tests, light transmission and haze measurement, and isothermal and nonisothermal crystallization behavior determinations. The PLA/PA11/SiO₂ (97.0/3.0) composite had approximately 10.8% less ultimate tensile strength than neat PLA, but it had greater ductility and approximately ninefold greater elongation at break. A dimple morphology was observed on the fractural surface of the PLA/PA11/SiO₂ composite, indicating that the incorporation of PA11 and nanosilica particles increased the ductility of the PLA matrix. PLA with less than 3 wt% of PA11 and 0.5 phr of nanosilica particles had an Izod impact strength of 8.72 kJ/m². PA11 and nanosilica particles effectively toughened this PLA polymer; they accelerated both isothermal and nonisothermal crystallization rates and increased the crystallinities of the resulting composites under isothermal and nonisothermal crystallization processes.     

The News You Choose: news media preferences amplify views on climate change

How do choices among information sources reinforce political differences on topics such as climate change? Environmental sociologists have observed large-scale and long-term impacts from news media and think-tank reports, while experimental science-communication studies detect more immediate effects from variations in supplied information. Applying generalized structural equation modeling to recent survey data, previous work is extended to show that political ideology, education and their interaction predict news media information choices in much the same way they predict opinions about climate change itself. Consequently, media information sources serve as intervening variables that can reinforce and, through their own independent effects, amplify existing beliefs about climate change. Results provide empirical support for selective exposure and biased assimilation as mechanisms widening political divisions on climate change in the United States. The findings fit with the reinforcing spirals framework suggesting partisan media strengthens climate change beliefs which then influences subsequent use of media.     

Handling the phosphorus paradox in agriculture and natural ecosystems: Scarcity,necessity, and burden of P

This special issue of Ambio compiles a series of contributions made at the 8th International Phosphorus Workshop (IPW8), held in September 2016 in Rostock, Germany. The introducing overview article summarizes major published scientific findings in the time period from IPW7 (2015) until recently, including presentations from IPW8. The P issue was subdivided into four themes along the logical sequence of P utilization in production, environmental, and societal systems: (1) Sufficiency and efficiency of P utilization, especially in animal husbandry and crop production; (2) P recycling: technologies and product applications; (3) P fluxes and cycling in the environment; and (4) P governance. The latter two themes had separate sessions for the first time in the International Phosphorus Workshops series; thus, this overview presents a scene-setting rather than an overview of the latest research for these themes. In summary, this paper details new findings in agricultural and environmental P research, which indicate reduced P inputs, improved management options, and provide translations into governance options for a more sustainable P use.     

The effects of the Fukushima disaster on nuclear energy debates and policies: a two-step comparative examination

Under what conditions do critical events trigger large-scale public discussion and mobilisation, and can these lead to policy change? In a comparative study of nuclear energy policy after the Japanese Fukushima disaster in March 2011, a theory-development approach is adopted, mobilising data collected from national news agencies’ newswires, public surveys, legislation and parliamentary databases, and newspaper editorials in 12 established democracies between March 2011 and March 2013. The analysis suggests two main hypotheses that can guide future research: critical events are more likely to trigger policy change when intense (contentious) mobilisation from policy challengers aligns with the views of the general public, and is backed by major political allies; and critical events are more likely to trigger intense (contentious) mobilisation when policy challengers articulate their opposition around pre-existing policy debates on the issue and resort to pre-existing organisational and mobilisation resources.     

Food: From Commodity to Commons

Our food and farming system is not socially, economically or ecologically sustainable. Many of the ills are a result of market competition driving specialization and linear production models, externalizing costs for environmental, social and cultural degradation. Some propose that market mechanisms should be used to correct this; improved consumer choice, internalization of costs and compensation to farmers for public goods. What we eat is determined by the path taken by our ancestors, by commercialization and fierce competition, fossil fuels and demographic development. Based on those, governments and the food industry are the choice architects who determine what we eat; consumer choice plays a marginal role. Using market mechanisms to internalize cost and compensate farmers for public goods has been proposed for decades but little progress has been made. There are also many practical, ethical and theoretical objections to such a system. The market is not a good master for a sustainable food system. Instead we need to find new ways of managing the food system based on food as a right and farming as a management system of the planet Earth. The solutions should be based on relocalization of food production and de-commodification of food and our symbionts, the plants and animals we eat.     

The Normative Limits of Consumer Citizenship

In political philosophy, citizenship is a key concept. Citizenship is tied to rights and duties, as well as to concepts of social justice. Recently, the debate on citizenship has developed a new direction in focusing on qualified notions of citizenship. In this contribution, I shall defend three claims. Firstly, consumer citizenship fits into the discussion of qualified notions of citizenship. Secondly, the debate on qualified notions of citizenship cannot be detached from the normative claims in the philosophy of citizenship more generally. In particular, duties and rights receive a distinct shape when debated in terms of “consumer citizenship”. Thirdly, I shall argue that further normative limits can be established by discussing qualified notions of citizenship as items of a list that need to cohere in normative terms. I shall pay particular attention to environmental citizenship.     

Consuming for the Sake of Others: Whose Interests Count on a Market for Animal-Friendly Products?

Many Europeans are concerned about the living conditions of farm animals because they view animals as beings that possess interests of their own. Against this background the introduction of an animal welfare label is being intensively discussed in Europe. In choosing a market-based instrument to take these concerns into account, normative judgments are made about the formation of preferences, the value system that is implicitly assumed, and the distribution of property rights. From the perspective of classical institutional economics it can be shown that the introduction of a label as an institutional change does not redefine institutions in a way that allows them to consider the interests of animals for their own sake. Rather, the label only redefines the property rights that humans have over animals. The market segregation into privileged and normal animals conflicts with the idea of equality between sentient animals. Within the group of humans only the interests of those who act on markets count. The commodification of their moral concerns assumes that people always decide based on their own interests, which can be traded off. The lexicographical ordering of preferences, which occurs when humans view animals as entities with rights, is not compatible with the normative assumptions of markets. Furthermore, interpreting animal suffering as market failure that can be corrected by labeling impedes a reasoned dialog within the society about the values and beliefs that serve as a basis for preference formation. Thus, an animal welfare label cannot replace a fundamental societal debate about legal standards on animal well-being.