Processing technologies for poly(lactic acid)

For a long time polymers have supplied most of common packaging materials because they present several desired features like softness, lightness and transparency. However, increased use of synthetic packaging films has led to a serious ecological problems due to their total non-biodegradability. Although their complete replacement with eco-friendly packaging films is just impossible to achieve, at least for specific applications like food packaging the use of bioplastics should be the future. The aim of this review was to offer a complete view of the state of the art on biodegradable polymer packages for food application.

Biodegradable polymers for food packaging: a review

Physical and mechanical properties of PLA, and their functions in widespread applications - A comprehensive review.

Poly(lactic acid) (PLA), so far, is the most extensively researched and utilized biodegradable aliphatic polyester in human history. Due to its merits, PLA is a leading biomaterial for numerous applications in medicine as well as in industry replacing conventional petrochemical-based polymers. The main purpose of this review is to elaborate the mechanical and physical properties that affect its stability, processability, degradation, PLA-other polymers immiscibility, aging and recyclability, and therefore its potential suitability to fulfill specific application requirements. This review also summarizes variations in these properties during PLA processing (i.e. thermal degradation and recyclability), biodegradation, packaging and sterilization, and aging (i.e. weathering and hygrothermal). In addition, we discuss up-to-date strategies for PLA properties improvements including components and plasticizer blending, nucleation agent addition, and PLA modifications and nanoformulations. Incorporating better understanding of the role of these properties with available improvement strategies is the key for successful utilization of PLA and its copolymers/composites/blends to maximize their fit with worldwide application needs.

Physical and mechanical properties of PLA, and their functions in widespread applications — A comprehensive review

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.

Poly(lactide) (PLA) polymers have garnered increasing attention in the last few years as food packaging materials because they can be obtained from renewable resources; their production consumes quantities of carbon dioxide; they can be recycled and composted; and their physical and mechanical properties can be tailored through polymer architecture. As a consequence, PLA is becoming a growing alternative as a ‘green’ food packaging material. PLA's optical, physical and mechanical properties have been compared to those of polystyrene (PS) and polyethylene terephthalate (PET), although studies comparing and showing the actual performance of PLA, PS and PET plastics containers are scarce. The purpose of this study was to investigate and compare the role of PLA in package sustainability for the food service industry. Two of the commonly used materials to make containers to package fresh food, PET and oriented polystyrene (OPS), were compared with oriented PLA (OPLA) and OPLA with 40% recycled content from the industrial trimming process. The recycled OPLA provides an opportunity for full material utilization and lower costs. This study involved a number of tests to quantify the physical, mechanical, barrier and compatibility properties that would affect the selection criteria for containers to be used for food service applications. Based on the data collected, OPLA, OPLA + 40% regrind, OPS and PET performances were evaluated. Exposure of the four materials to vegetable oil and weak and strong acids show a minimal reduction in the performance of these polymers. At ambient temperature, PET has the highest impact resistance, followed by OPLA, OPS and OPLA + 40% regrind. In terms of barrier properties, PET shows the highest oxygen barrier, followed by OPLA, OPLA 40% recycled content, and OPS. Thus, OPLA and OPLA with 40% recycled content can be used for fresh food applications as well as OPS and PET, and in many situations it performs better than OPS and PET. Copyright © 2005 John Wiley & Sons, Ltd.

http://www.burchamintl.com/papers/petpapers/46_gpec05.pdf

Evaluation of oriented poly(lactide) polymers vs. existing PET and oriented PS for fresh food service containers

There is a significant amount of goods that are transported using tractor trailers. Most high-value products, such as electronics, highly perishable goods like fruits and vegetables and most retail consumer products, are shipped using trucks in North America. It is therefore important to measure and quantify the levels of vibration that occur inside this mode of transport as it pertains to damage. Vibration levels inside a tractor-trailer are a function of the road surface, the speed of the vehicle, the type of suspension and the structure of the trailer. The purpose of this study was to determine the levels of vibration as a function of trailer suspension at normal operating speeds in commercially used truck equipment, over 16000km of road surfaces in North America. Copyright © 2006 John Wiley & Sons, Ltd.

Measurement and analysis of US truck vibration for leaf spring and air ride suspensions, and development of tests to simulate these conditions

Today's demanding distribution challenges require engineers to choose from various types of materials, design and construction methods, to develop containers that can deliver goods with minimal damage. The challenge is even greater when packing and shipping goods which are perishable and sensitive to both physical and climatic changes in environment. In recent years the type of packaging material used to design and construct containers has undergone more scrutiny than ever, due to environmental challenges. This study focuses on two types of containers that have been designed and are being used to pack and ship fresh fruits and vegetables. The study compares the re-usable plastic containers to single-use display-ready paper corrugated trays. Results show that, based on the scope of this study and comparing 10 different produce items, such as apples, carrots, grapes, oranges, onions, tomatoes, strawberries, etc., the re-usable plastic containers require 39% less total energy, produce 95% less total solid waste and generate 29% less total greenhouse gas emissions. This study focused on the North American market. Major European nations have been using a large number of re-usable plastic containers for these types of fresh produce for the past three decades. This study was initiated by the Franklin Associates, an independent consulting firm for allowing an in-depth review of all data and results from a two year study titled: Life Cycle Inventory of Reusable Plastic Containers and Display-Ready Corrugated Containers Used for Fresh Produce Applications. Copyright © 2006 John Wiley & Sons, Ltd.

Life cycle inventory and analysis of re‐usable plastic containers and display‐ready corrugated containers used for packaging fresh fruits and vegetables

The past decade has shown a great increase in the number of direct to consumer shipments of products and packages. As a result, parcel delivery companies like DHL, FedEx, UPS and the USPS have strengthened their presence in air transport. Using cargo planes, they route packages from various destinations to large airport hubs, where they sort millions of packages and ship them to their destinations the next morning. There is a continuous need to quantify what happens to these packages as they are handled both manually during collection and delivery and on large high-speed conveying and sortation equipment at hubs. This study measured and compared shock and drop events for these carriers during next-day and 2-day shipping service. Copyright © 2006 John Wiley & Sons, Ltd.

Measurement and analysis of the next‐day air shipping environment for mid‐sized and lightweight packages for DHL, FedEx and United Parcel Service

This study measured and analysed the parcel shipping environment within Federal Express. The package sizes and weights monitored in this study represent the ‘light-weight’ and 'small-size' packages within the FedEx handling system. Five packages, ranging in size from 0.18 × 0.19 × 0.13 m to 0.36 × 0.37 × 0.31 m, and weighing 1.9–2.5 kg, were shipped, both with and without warning labels with the text ‘Fragile – Handle With Care’. The shipments were done between Michigan and California or Florida using the second-day air shipment mode. The data showed that neither the package size/weight nor the labels had any significant effect on the severity of drop heights. The highest drop height measured was 1.85 m. The data is presented in terms of drop heights associated with the 90, 95 and 99th percentile of occurrence. Impact orientation is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.

Jagjit Singh

Papers

Evaluation of oriented poly(lactide) polymers vs. existing PET and oriented PS for fresh food service containers

Measurement and analysis of US truck vibration for leaf spring and air ride suspensions, and development of tests to simulate these conditions

Life cycle inventory and analysis of re‐usable plastic containers and display‐ready corrugated containers used for packaging fresh fruits and vegetables

Measurement and analysis of the next‐day air shipping environment for mid‐sized and lightweight packages for DHL, FedEx and United Parcel Service

Measurement and analysis of the second‐day air small and light‐weight package shipping environment within Federal Express