Environmental, economic, and safety challenges have provoked packaging scientists and producers to partially substitute petrochemical-based polymers with biodegradable ones. The general purpose of this review is to introduce poly-lactic acid (PLA), a compostable, biodegradable thermoplastic made from renewable sources. PLA properties and modifications via different methods, like using modifiers, blending, copolymerizing, and physical treatments, are mentioned; these are rarely discussed together in other reviews. Industrial processing methods for producing different PLA films, wrappings, laminates, containers (bottles and cups), are presented. The capabilities of PLA for being a strong active packaging material in different areas requiring antimicrobial and antioxidant characteristics are discussed. Consequently, applications of nanomaterials in combination with PLA structures for creating new PLA nanocomposites with greater abilities are also covered. These approaches may modify PLA weaknesses for some food packaging applications. Nanotechnology approaches are being broadened in food science, especially in packaging material science with high performances and low concentrations and prices, so this category of nano-research is estimated to be revolutionary in food packaging science in the near future. The linkage of a 100% bio-originated material and nanomaterials opens new windows for becoming independent, primarily, of petrochemical-based polymers and, secondarily, for answering environmental and health concerns will undoubtedly be growing with time.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1541-4337.2010.00126.x

Poly-Lactic Acid: Production, Applications, Nanocomposites, and Release Studies.

PLA composites: From production to properties

The article contains sections titled: 

1.	Introduction	
2.	Historical Outline	
2.1.	Historical Technological Outline and Industrial Resources	
2.2.	The Beginning–A Digest	
2.2.1.	Sugar Production	
2.2.2.	Starch Hydrolysis	
2.2.3.	Wood Saccharification	
2.2.4.	Furfural	
2.2.5.	Cellulose and Pulp	
2.2.6.	Levulinic Acid	
2.2.7.	Lipids	
2.2.8.	Vanillin from Lignin	
2.2.9.	Lactic Acid	
2.3.	The Origins of Integrated Biobased Production	
3.	Situation	
3.1.	Some Current Aspects of Biorefinery Research and Development	
3.2.	Raw Material Biomass	
3.3.	National Vision and Goals and Plan for Biomass Technology in the United States	
3.4.	Vision and Goals and Plan for Biomass Technology in the European Union and Germany	
4.	Principles of Biorefineries	
4.1.	Fundamentals	
4.2.	Definition of the Term “Biorefinery”	
4.3.	The Role of Biotechnology	
4.3.1.	Guidelines of Fermentation Section within Glucose-product Family Tree	
4.4.	Building Blocks, Chemicals and Potential Screening	
5.	Biorefinery Systems and Design	
5.1.	Introduction	
5.2.	Lignocellulosic Feedstock Biorefinery	
5.3.	Whole-crop Biorefinery	
5.4.	Green Biorefinery	
5.5.	Two-platform Concept and Syngas	
6.	Biorefinery Economy	
7.	Outlook and Perspectives

Biorefineries – Industrial Processes and Products

This chapter examines the physical and mechanical properties of biodegradable polymers derived from renewable sources and petrochemical sources with a focus on their applications Polymers from renewable sources include poly(lactic acid), polyhydroxyalkanoates (PHA), and thermoplastic starch (TPS) Polymers from petrochemical sources include aliphatic polyesters and copolyesters, aromatic polyesters and copolyesters, poly(caprolactone), poly(esteramide), and poly(vinyl alcohol) The physical properties, based on which biodegradable polymers are categorized, are their melt flow rate, density, and transparency Mechanical properties include their tensile strength at yield, elongation at yield, and tensile modulus There are many applications of compostable polymer materials in the commercialized or development/demonstration stage They are used in the packaging industry, in agriculture and horticulture, in short life consumer goods, and long life consumer goods The major markets of compostable polymer materials are agriculture, fisheries, civil engineering, constructions, food packaging, and many more The increased interest in compostable polymers is a response to the growing price of petroleum and growing consumer demand for sustainable products Improvement in processing technologies and the effect of scale-up has decreased the price of compostable polymers

Properties and applications

Future plastic materials will be very different from those that are used today The increasing importance of sustainability promotes the development of bio-based and biodegradable polymers, sometimes misleadingly referred to as ‘bioplastics’ Because both terms imply “green” sources and “clean” removal, this paper aims at critically discussing the sometimes-conflicting terminology as well as renewable sources with a special focus on the degradation of these polymers in natural environments With regard to the former we review innovations in feedstock development (eg microalgae and food wastes) In terms of the latter, we highlight the effects that polymer structure, additives, and environmental variables have on plastic biodegradability We argue that the ‘biodegradable’ end-product does not necessarily degrade once emitted to the environment because chemical additives used to make them fit for purpose will increase the longevity In the future, this trend may continue as the plastics industry also is expected to be a major user of nanocomposites Overall, there is a need to assess the performance of polymer innovations in terms of their biodegradability especially under realistic waste management and environmental conditions, to avoid the unwanted release of plastic degradation products in receiving environments

Environmental performance of bio-based and biodegradable plastics: the road ahead

Cargill Dow LLC produces a new packaging and fiber material – polylactide (PLA) – from annually renewable resources. The presence of the company and the PLA polymer on the industrial scene signals the emergence of a new model for industrial development in the twenty-first century. During the nineteenth century people relied predominantly on a wide range of natural materials, such as wood, hides, wool and starch, to provide the essentials of then-modern life. This picture changed significantly during the twentieth century, when people in developed countries experiencing the industrial revolution became almost totally dependent on fossil materials to produce the fuels, polymers and chemicals required for modern life. With exponential growth in the demand for fossil raw materials in both developing and developed countries today, the question increasingly posed is how we will derive the materials we will need in the twenty-first century. An increasingly broad range of experts and analysts have concluded that new – or in some very important ways, ‘‘old’’ – raw materials will become the foundation of packaging materials and fibers in a world challenged by the interrelated problems of depletion of fossil resources and of proliferation of global climate changing emissions, pollutants and solid wastes. A consensus remains that fossil resources will be required and used for quite some time, but it is also hardly doubted that maintaining and enhancing quality of life for a growing populationaround theglobe compels the developmentofnew technologies to produce packaging materials and fibers from new ‘‘old’’ resources like traditional agricultural crops (e.g., corn, wheat, sugar beets) and other grown biomass materials. It is in this new and renewed reality of renewable rawmaterials reliance that Cargill Dow LLC emerges. The objective of this paper is to answer the question: ‘‘What makes NatureWorks PLA a more sustainable polymer?’’ To answer this question the article addresses applications and marketing of PLA, costs, today’s and future renewable raw material resources, reduction of fossil fuels and the associated emissions of green house gases, waste management options, and manufacturing processes.

Jeff Kolstad

Papers

The sustainability of NatureWorks polylactide polymers and Ingeo polylactide fibers: an update of the future.