Green polymers derivatives

Since 1989, Cargill, has invested some 750 million to develop and commercialize polylactic acid (tradename NatureWorks). Its Nebraska plant, with an annual capacity of 140,000 metric tons, opened in 2002. Thus, polylactides, combining favorable economics with green sustainability, are poised to compete in large-volume markets that are now the domain of thermoplastic polymers derived from petrochemical sources. 

Hooke s law relates stress (or strain) at a point to strain (or stress) at the same point and the structure of classical elasticity (see e.g. Love, Sokolnikoff) is built upon this linear relation. There are other relationships possible. One, as outlined above (see e.g. Green and Adkins) involves the large strain tensor Cjj which does not bear a simple relationship to the stress tensor, another involves the newer concepts of micropolar and micromorphic elasticity in which not only the stress but also the couple at a point must be related to the local variations of displacement and rotation. A third, which may prove to be very relevant to polymers, derives from non-local field theories in which not only the strain (or displacement) at a point but also that in the neighbourhood of the point needs to be taken into account. In polymers, where the chain is so much stiffer along its axis than any interchain stiffness (consequent upon the vastly different forces along and between chains) the displacement at any point is quite likely to be influenced by forces on chains some distance away. 

Green polymer synthesis using starting materials derived from renewable resources (rather than petroleum) is discussed in Section 30.8. 

Green fibers derived from melt-spinnable polymers have been cured in an ammonia atmosphere, then pyrolyzed in ammonia and nitrogen atmospheres to generate at 1800 °C boron nitride fibers with excellent mechanical properties. It was interesting to note that boron nitride fibers, with controlled mechanical properties and crystallinity, could be produced through simply changing the meltspinning conditions (Table 14.1) [35]. 

It has been confirmed that the presence of bridge-type bonds in such poly (B-alkylaminoborazines) confers flexibility and an inaeased melt-spirmability, thus leading to the conclusions that melt-spinnability inaeases from 1- to 4-daived polymers. In addition, the ceramic yield is reduced with the increased proportion of -NlCHj) in the B-(alkylamino)borazine leading to important shrinkages during the furlha- polymer-to-ceramic conversion of green fibers derived therefrom. Hence, it is relevant to assume... 

Green polymer synthesis—the preparation of polymers by environmentally friendly methods using starting materials that are not derived from petroleum—is an active area of research. One example is the polymerization of tulipalin A, a natural product derived from tulips, to afford polytulipalin. Polytulipalin has properties similar to some petroleum-derived polymers, but its availability from a natural source has made It a possible attractive alternative to these polymers. Polymerization occurs in the presence of a strong base (B ), and each new C-C bond in polytulipalin is formed by a Michael reaction. Draw a stepwise mechanism for the formation of one C-C bond in polytulipalin. (See Section 30.8 for other aspects of green polymer chemistry.)... 

Other interesting and growing enviromnentally friendly indnstries which ACOMP may be applied to are biofuels and green polymers made from renewable feedstocks such as ethanol-derived ethylene and other processes. ACOMP may eventnaUy be nsed to monitor fermentation processes to gange conversion of biomass to the active biofuel or chemical feedstock. This is a completely novel and untested application for the technology, but could be of substantial commercial and enviromnental benefit. 

Sasmal, A., Nayak, P.L., Sasmal, S., 2009. Degradability studies of green nanocomposites derived from soy protein isolate (Spi)-furfural modified with organoclay. Polymer-Plastics Technology and Engineering 48, 905—909. 

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