There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

Plastic waste is currently generated at a rate approaching 400 Mt year–1. The amount of plastics accumulating in the environment is growing rapidly, yet our understanding of its persistence is very...

Degradation Rates of Plastics in the Environment

Poly(lactic acid)-Mass production, processing, industrial applications, and end of life.

Over the past four decades, global plastics production has quadrupled1. If this trend were to continue, the GHG emissions from plastics would reach 15% of the global carbon budget by 20502. Strategies to mitigate the life-cycle GHG emissions of plastics, however, have not been evaluated on a global scale. Here, we compile a dataset covering ten conventional and five bio-based plastics and their life-cycle GHG emissions under various mitigation strategies. Our results show that the global life-cycle GHG emissions of conventional plastics were 1.7 Gt of CO2-equivalent (CO2e) in 2015, which would grow to 6.5 GtCO2e by 2050 under the current trajectory. However, aggressive application of renewable energy, recycling and demand-management strategies, in concert, has the potential to keep 2050 emissions comparable to 2015 levels. In addition, replacing fossil fuel feedstock with biomass can further reduce emissions and achieve an absolute reduction from the current level. Our study demonstrates the need for integrating energy, materials, recycling and demand-management strategies to curb growing life-cycle GHG emissions from plastics. The life-cycle GHG emissions from plastics are expected to increase. Here, it is shown that an aggressive strategy of decarbonizing energy infrastructure, improving recycling, adopting bio-based plastics and reducing demand is required to keep emissions below 2015 levels.

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Strategies to reduce the global carbon footprint of plastics

Carbon dioxide offers an accessible, cheap and renewable carbon feedstock for synthesis. Current interest in the area of carbon dioxide valorisation aims at new, emerging technologies that are able to provide new opportunities to turn a waste into value. Polymers are among the most widely produced chemicals in the world greatly affecting the quality of life. However, there are growing concerns about the lack of reuse of the majority of the consumer plastics and their after-life disposal resulting in an increasing demand for sustainable alternatives. New monomers and polymers that can address these issues are therefore warranted, and merging polymer synthesis with the recycling of carbon dioxide offers a tangible route to transition towards a circular economy. Here, an overview of the most relevant and recent approaches to CO2-based monomers and polymers are highlighted with particular emphasis on the transformation routes used and their involved manifolds.

Advances in the use of CO2 as a renewable feedstock for the synthesis of polymers

Concurrent solvent induced crystallization and hydrolytic degradation of PLA by water-ethanol solutions

Most of the physicochemical properties in polymers such as activity and partition coefficients, diffusion coefficients, and their activation with temperature are accessible to direct calculations from first principles. Such predictions are particularly relevant for food packaging as they can be used (1) to demonstrate the compliance or safety of numerous polymer materials and of their constitutive substances (e.g. additives, residues…), when they are used: as containers, coatings, sealants, gaskets, printing inks, etc. (2) or to predict the indirect contamination of food by pollutants (e.g. from recycled polymers, storage ambiance…) (3) or to assess the plasticization of materials in contact by food constituents (e.g. fat matter, aroma…). This review article summarizes the classical and last mechanistic descriptions of diffusion in polymers and discusses the reliability of semi-empirical approaches used for compliance testing both in EU and US. It is concluded that simulation of diffusion in or th...

Predicting Diffusion Coefficients of Chemicals in and through Packaging Materials

The paper presents a harmonized description of the diffusion of solutes with repeated aromatic jumping units (JU) in entangled aliphatic polymers above their Tg. It is shown that the trace diffusion coefficients, D, are scaled with the number of JU or equivalently with solute molecular mass, M, as M–1M–Kα/(T–Tg + Kβ), where Kα and Kβ are temperature-equivalent parameters related to Williams–Landel–Ferry (WLF) ones. The scaling of diffusion behaviors of linear aliphatic and aromatic solutes appear separated by a temperature shift, Kβ, of ca. 91 K. The effects of the number of JU and the distance between two JU were specifically probed in several aliphatic polymers (polypropylene, polylactide and polycaprolactone) at different temperatures above Tg with two homologous solute series: short oligophenyls and diphenylalkanes. An extended free-volume theory for many JU was accordingly inferred to account for the observed statistical independence between the fluctuations of the free volumes probed by each JU and ...

Diffusion of Aromatic Solutes in Aliphatic Polymers above Glass Transition Temperature

A material is defined as “barrier” when it is able to delay the diffusion of a penetrant. There are few possibilities to modulate the barrier properties of a prescribed material (e.g. packaging material). Most of conventional technological strategies aim at increasing the tortuosity path of the penetrant by adding obstacles. Such obstacles could be obtained either by creating a crystalline morphology or by adding of nano-fillers. The gain in diffusion barrier depends on the shape factor of obstacles, their concentration and orientation according to the main direction of transfer. In this PhD work, a novel direction to improve the barrier property has been studied; its principles have been early formalized independently from theoretical considerations on random walk on heterogeneous energy surfaces and from modeling of reactivity in heterogeneous catalysis. The central idea relies on increasing retention times instead of diffusion path lengths by incorporating nano-adsorbents (i.e. active obstacles) in the material. In this case, the considered material becomes a barrier specific to one or a family of solutes. This new concept has been tested on organic solutes to develop new barrier materials (e.g. biobased food packaging, materials for fuel tank…). The results brought out the engineering principles of such materials and experimental evidences to support the concepts. In particular, an extended free-volume theory has been developed to separate interactions with active surfaces (i.e. montmorillonites (MMT) in this work) from free-volume related effects in the polymer. Sorption properties of pristine MMT and organo-modified ones have been characterized experimentally and by molecular simulation to derive conditions where the partition coefficient Kcontrast between the surface of MMT and tested polymers (i.e. polycaprolactone (PCL), polyvinyl alcohol (PVA)) could be much greater than unity. PVA materials containing pristine MMT exhibited the most promising barrier properties to studied model solutes, which can be activated by decreasing temperature and whose selectivity can be controlled by varying the relative humidity. The blocking effects were in good agreement with the proposed description of “trapping” of organic solutes by intercalation in MMT galleries and on its enthalpic and entropic control.

Xiaoyi Fang

Papers

Poly(lactic acid)-Mass production, processing, industrial applications, and end of life.

Concurrent solvent induced crystallization and hydrolytic degradation of PLA by water-ethanol solutions

Predicting Diffusion Coefficients of Chemicals in and through Packaging Materials

Diffusion of Aromatic Solutes in Aliphatic Polymers above Glass Transition Temperature

Design and engineering of barrier materials including nano-adsorbents