Polyolefins agricultural applications

R. Scaffaro, L. Botta, F.P.L. Mantia, Preparation and characterization of polyolefin—based nanocomposite blown films for agricultural applications. Macromol. Mater. Eng. 294, 445-454 (2009)... 

Manufacturers and users of oxo-biodegradable polyolefins view with concern the development of standards for degradable polymers which demand a high level of mineralization as the primary criterion. This protocol was originally developed for hydro-biodegradable polymers, which will primarily end up in sewage. For these polymers and in this application, such test methods are entirely acceptable but they are totally inappropriate for compost, litter and agricultural applications. 

Commercial polyolefins show no significant reduction in molar mass in typical ambient biometric tests over many months or even years. The resistance of hydrocarbon polymers to biodegradation during use is one of their major advantages in agricultural application over bio-based plastics. The useful life of photo-biodegradable polyolefins is controlled commercially by appropriate transition metal complexes in which the ligands are... 

Table 17.7 lists the products currently being examined in agricultural applications in Taiwan. Piaster SG and EPI TDPA are oxo-biodegradable polyolefins (see Chs 3 and 12) and have been shown to oxo-biodegrade after initiation by light and heat. PE-starch blends may contain transition metal ions... 

The principal polymers used in blown film production are polyolefins, although other polymers can also be used. The major applications are those that require biaxial strength, and include bags of all kinds, as well as agricultural and construction film. In food packaging, coextruded structures with three to five layers, or even more, are common, with major markets including packaging for cereal, meat, snacks, and frozen foods. 

Addition of micro- or nanofiUers or additives to the polyolefins can improve their properties for different modem applications such as in the automotive, furniture, medical, packaging, electrical, transportation, constmction, textile, and agriculture industries. These industries have been increasing over the last few decades. Additives can include diflerent shapes such as flakes, fibers, and particulate types. It can be of natural or synthetic nature. The additives can improve the performance of the new composites or nanocomposites of the polyolefins. 

Prepared filaments and fibres are applied not only in the floor coverings as the most important utilization for PP, but also medical, hygienic, apparel, automotive and/or agricultural sectors became crucial, for applications such as disposable diapers, sports underwear and equipment, artificial grass, geo textiles, ropes, car seats, oil wipes, wet and dry filters or membranes. Physical and chemical properties of polyolefins fibres are developed for many applications, in order to increase comfort characteristics, tensile strength, and/or other utility properties they are often blended, co-processed or combined with other materials such as polar acrylics, wool, bonding agents, hydrophilic fillers, or stabilizers. 

Coextrusion and lamination processes have been described extensively in the patent literature. The technology usually involves multilayer structures utilizing, as an adhesive layer, a compound of PVDF with another material, which provides the bonding to the substrate. In this way, the full benefits of a thin film of PVDF may be realized (121). Another approach using acrylic alloys with PVDF sometimes achieves adherence to various substrates without the tie layer necessary for the pure PVDF film (122). The full breadth of options available by these technologies to protect surfaces with weatherable PVDF surfaces has been reviewed (123). Surface PVDF layers on polyolefins has been a particular technology of interest with respect to suitable finishes in cost effective parts for exterior automotive and agricultural equipment applications (124). 

Research activities directed towards the application of polyolefins in agriculture have been particularly concerned with making products which can modify or control environmental conditions. The reason for this is the link between yields, quantity and quality of the crops, and the condition of the soil and of the plant environment. In field cultivation the natural conditions, such as soil and climate can neither be optimized nor modified plastic products are an instrument available to the grower which aims to reduce the environmental limitations. 

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