Tailoring Hydrocarbon Polymers and All‐Hydrocarbon Composites for Circular Economy

Abstract

The world population will rapidly grow from 7 to 9 billion by 2050 and this will parallel a surging annual plastics consumption from today's 350 million tons to well beyond 1 billion tons. The switch from a linear economy with its throwaway culture to a circular economy with efficient reuse of waste plastics is therefore mandatory. Hydrocarbon polymers, accounting for more than half the world's plastics production, enable closed‐loop recycling and effective product‐stewardship systems. High‐molar‐mass hydrocarbons serve as highly versatile, cost‐, resource‐, eco‐ and energy‐efficient, durable lightweight materials produced by solvent‐free, environmentally benign catalytic olefin polymerization. Nanophase separation and alignment of unentangled hydrocarbon polymers afford 100% recyclable self‐reinforcing all‐hydrocarbon composites without requiring the addition of either alien fibers or hazardous nanoparticles. Recycling of durable hydrocarbons is far superior to biodegradation. The facile thermal degradation enables liquefaction and quantitative recovery of low molar mass hydrocarbon oil and gas. Teamed up with biomass‐to‐liquid and carbon dioxide‐to‐fuel conversions, powered by renewable energy, waste hydrocarbons serve as renewable hydrocarbon feedstocks for the synthesis of high molar mass hydrocarbon materials. Herein, an overview is given on how innovations in catalyst and process technology enable tailoring of advanced recyclable hydrocarbon materials meeting the needs of sustainable development and a circular economy.

Beyond Mechanical Recycling: Giving New Life to Plastic Waste

“…Polyolefin-based waste has historically been treated via gasification or unselective pyrolysis.There is renewed interest in the conversion of PE and PP back into monomer and/or oligomers.T his could be more easily achieved, if the plastics are designed with recycling in mind, for example,byavoiding additives that lead to degradation during melting and reextrusion or that cause catalyst deactivation in thermal processes.M ülhaupt et al discuss this so-called "design for recycling" approach [107] for polyolefins. [108] This Review and other literature from Mülhaupt et al [109] discuss the production of 100 %p olyolefinic plastics and composites without additives.T his can be achieved with multisite polymerization catalysts and specialized injection-molding processes,such as oscillating packing injection molding.This approach removes the necessity of producing different polymers in different plants,a voids the use of additives,s uch as glass fiber, and generates ap roduct that could potentially be depolymerized with polymer synthesis catalysts like Ziegler-Natta. The synthesis and production of PP or PE-based plastics or composites in this manner, [110] can potentially be more impactful with regard to production efficiencyand ecological footprint.…”

Die nächste Generation des Recyclings – neues Leben für Kunststoffmüll

“…[105] Beispielsweise kçnnten Zusatzstoffe vermieden werden, die dazu führen, dass der Kunststoff während des Einschmelzens und Neuformens degradiert oder Katalysatoren deaktiviert, die in chemischen Recyclingverfahren eingesetzt werden. Andere Autoren [106] sowie Mülhaupt et al in ihrem Übersichtsartikel [107] beschreiben die Produktion von Polyolefinen ganz ohne Zusatzstoffe.D ies kann erreicht werden, wenn fürd ie Polymerisation ein bestimmter Katalysator mit mehreren aktiven Stellen verwendet wird oder ein bestimmtes Spritzgießverfahren, wie das "oscillating packing injection molding", zum Einsatz kommt. Damit ist es nicht mehr notwendig, die verschiedenen Polymere in unterschiedlichen Produktionsstätten zu produzieren.…”

Intracrystalline Dynamics in Oligomer‐Diluted Poly(Ethylene Oxide)

“…The FIDs were decomposed into three signal fractions (see Figure 2a)), [28][29][30] the highly dipole-dipolecoupled crystalline fraction f c , the intermediate phase f i and the amorphous fraction f a using the following three component fit wherein the fit parameters of the mobile phase are known form the additional measurement of a MAPE-filtered FID with a filter duration of 0.6 μs for the pure and Φ = 0.1 samples and 0.45 μs for the samples with Φ ≥ 0.3. [30,31] The crystalline fraction f c (t) is described by the so-called Abragram function, which describes a strongly coupled FID. The transverse relaxation times 2, * T i and 2, * T a are in the range of a few to several hundreds of microseconds.…”

“…[4] Controlling and varying the properties of simple homopolymers is a cornerstone of improving the polymers' recyclability, toward a circular and thus more sustainable plastics economy. [5] Semicrystalline polymers can be subdivided into two major classes, namely crystal-fixed and crystal-mobile polymers. Diffusive chain mobility within and through the crystalline lamellae enables high crystallinity, [6,7] and is the molecular basis of the deformability of polymer crystals, explaining important performed by ref.…”