Consumer awareness of sustainable plastic solutions, government interest in the reduction of greenhouse gas emissions, and a pervasive general desire to eliminate fossil fuel independence all contribute to market growth of biodegradable plastics.
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Nowhere is this more evident than in Western Europe, as multiple household and business products are now being manufactured using biodegradable plastics, such as:. Europe is the place to watch, as Europeans are particularly motivated to reduce marine litter. Another reason that Western Europe leads the way in biodegradable plastics is that their landfill disposal costs — calculated by adding together landfill gate fees plus landfill taxes — are substantially higher than those in Central and Eastern Europe and North America.
In , global demand for these polymers is , metric tons, but total consumption of biodegradable polymers is expected to increase to almost , metric tons by Hackett also noted that biodegradable polymer use has grown more slowly or stagnated in places that lack mandates.
Very few major cities or municipalities currently have the necessary infrastructure in place. An important distinction needs to be made between the potential for biodegradable polymers and their actual decomposition.
Biodegradable polymers are compostable only in special industrial composting facilities, which operate at higher temperatures than home compost piles. Indeed, composting of plastics waste was negligible as recently as Carolyn Fortuna Carolyn Fortuna, Ph. As part of her portfolio divestment, she purchased 5 shares of Tesla stock. Please follow her on Twitter and Facebook. Table 2 lists some of these. It may be seen that properties depend on the matrix, reinforcement and processing method used. Some details are given below:. Among the biodegradable composites, these composites are extensively studied.
Good adhesion, as revealed by the fractographs of these composites was reported to be the reason for these properties. On the other hand, the thermal behavior of these biocomposites showed an increase of glass transition temperature and two transition peaks in the DSC curve. It was observed that the glycerol content reduced the starch degradation, while increasing fiber content, increased degradation. Mercerization treatment of the fibers further improved in these values over their untreated counterparts.
Further, mercerization treatment of fibers improved these properties for coir and jute respectively, while they decreased in the case of sisal. All these results were explained by SEM studies relating them to the adhesion between the fibers and matrix.
In the former case of curaua fibers, both tensile strength and failure strain increased and almost two times for the alkali treatment over the untreated fiber while significant increase of tensile strength of both composites over the matrix However, failure strain of matrix 0. Young's modulus of both the composite remained almost constant while the value was significantly higher than that of the matrix.
In the case of coir-starch-EVOH-glycerol composites, increase in tensile strength and reduction in ductility of the matrix was observed with increasing fiber content, while no significant changes in crystalline structure [ 11 ]. Large pull outs in the composites indicated poor adhesion between the fiber and the matrix. Biodegradability of composites was better than that of the matrix.
These results have been explained as due to good interfacial adhesion observed in their morphology. Biodegradability also improved with the addition of fibers except slow down of this in the case of increasing coir fiber content in the composite. This system is the second highest researched system due to the excellent dispersability of fibers achieved in PHBs compared with synthetic polymers [ 3 ].
However, no changes in these properties were observed with the surface modification of the wood flour by either NaOH or corona electric discharge, which changes surface energy of fibers. On the other hand, the Young's modulus of these increased in a slightly different order.
In addition, crystallinity was found to decrease in similar order without any variation of the melting temperature for any combination. Above results suggested that the natural fibers can certainly improve only stiffness, while bagasse fibers imparted increase in the impact strength. Another reported results of effects of different types of matrix and fibers on the tensile properties indicated high tensile strength in PHB containing recycled cellulose fibers, while low values for these properties in wood flour and its pulp containing PHB [ 3 ].
Former composites showed decreasing viscosity with shear rate. The mechanical properties of these composites were reported to be dependent on fiber orientation.
SEM of fractured composites showed coating of flours by matrix, suggesting good fiber-matrix adhesion. Very little is reported on the development of biodegradable hybrid and nanocomposites based on Brazilian raw materials. This aspect needs more attention in view of the advantages these new generations of composites offer for a variety of applications including strategic sectors.
However, possibility exists to improve the properties of biodegradable nanocomposites further, which may open up the possibility for these composites to be used even in structural applications. While systematic studies on the characterization of some of the fibers and their composites are reported [ 3 , 8 , 10 , 13 , 14 ] including two patents, which have also been filed, others are being published.
Demand For Biodegradable Plastics Expected To Surge
Preliminary results on these composites with commercial and recovered glycerol byproduct of biodiesel and different amounts of banana wt. The properties of the fibers rather than the properties of the matrix dictated the morphology of these composites. Starch coating on bagasse fibers indicated good bonding between these fibers and the matrix compared with the free surface of banana fibers. Marginal improvements in tensile strength properties of these composites compared to those of the matrix were observed with their dependence on the processing methods with automatic control of temperature and applied pressure for composites; tensile properties of composites showed improved properties for the same amount of fiber content irrespective of type of glycerol used.
Demand For Biodegradable Plastics Expected To Surge | CleanTechnica
Crude glycerin produced more homogeneous composites, which led to better properties than those produced with commercial glycerol, which offered possible use to the main co-product of the biodiesel industry, without any requirement for its chemical treatment and upgrading.
Studies on cassava starch with coir and sisal fibers are continuing. Also, castor bean oil cake could partially replace starch or vice versa to produce biodegradable composites, which might have a great impact due to their large quantities usage, which otherwise could pose environmental hazards. Further, among the three lignocellulosic fibers used in this study, sugarcane bagasse fibers seemed to be the most favored followed by banana fibers and then Luffa cylindrica fibers based on the properties exhibited by their composites.
Another interesting observation was that crude glycerin gave comparable properties when used in composites suggesting the use of this material to replace expensive commercial grade glycerol.
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These results are being published elsewhere. Zirconium powder was used to get good homogenization of the composite produced whereby better mechanical properties could be achieved with low scatter in the values. No significant change in the structure was observed in the composite as seen by X-ray diffraction studies. Morphology studies indicated that granular structure of the matrix was destroyed during the thermo processing whereby homogenous phase was resulted.
Studies on castor oil seed-sponge guard-Luffa cylindrica and Balsa or Raft wood fibers are being continued. PHB and PHB containing different amounts of sugarcane bagasse fibers with and without steam explosion SE fibers showed [ 13 ] that more or less similar stress-strain curves for both the matrix and its composites, with differing slopes and strain at failure. This suggested a change in the behavior of PHB with the incorporation of sugarcane bagasse fibers due to the debonding with the matrix, leading to the beginning of the fracture of the composite as observed in fractographs.
Further, steam exploded fiber containing composites 5 and 30 wt. The randomly distributed raw bagasse fiber leads to higher values. Also, identical values for crystallinity were obtained from both DSC and X-ray diffraction techniques. Surface defects on the fibers, lack of bonding between the untreated bagasse fibers and PHB, presence of some air bubbles leading to defects in the samples and lowering of PHB crystallinity under pressure were some of the causes for the observed strength properties of composites. An abrupt decrease in the loss modulus E" supplemented this result.
Despite the fact that the environmentally friendly composites, provide designers new alternatives to meet challenging requirements, very few biodegradable composites have been developed and marketed even on the world scenario leave Brazil alone. This is contrary, to many biopolymer products, which are developed and marketed.
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