This study deals with the tensile drawing behavior of a polylactide material containing 4% of d-stereoisomer units, in the amorphous state. The draw temperature domain spanned from the glass transition to the onset of thermal crystallization, namely 70−100 °C. The stress−strain curves exhibit a strain-hardening strongly sensitive to the draw temperature regarding both the onset and the slope of the phenomenon. A detailed structural investigation reveals that various strain-induced phase changes take place depending on the draw temperature. For T d = 70 °C, a mesomorphic form develops from the strain-oriented amorphous chains, starting at a strain level ε ≈ 130%. In the case T d = 90 °C, a well-defined crystalline phase grows beyond the strain ε ≈ 250%. In the midtemperature range, i.e. T d = 80 °C, both the mesomorphic and the crystalline phases are generated in parallel. In all cases, the final weight content of ordered phases at rupture was roughly 30%, irrespective of their form. The observed evolution with increasing draw temperature of the strain-induced structure from mesomorphic to crystalline is quite surprising with regard to the concomitant drop of the strain-hardening. Indeed, if the latter finding is consistent with the thermal activation of plasticity, it also means that the mesomorphic form is almost as much cohesive as the crystalline form in spite of its imperfect ordering. The occurrence of the mesomorphic form is specifically discussed in terms of both chain mobility and thermodynamic metastability.

Nano-sized cellulose materials has recently become topical in the sphere of sustainable materials. The two key groups of nanocelluloses (NCs) are (1) nanofibrillated cellulose (NFC) and (2) cellulose nanocrystals (CNC). They are often considered as second-generation renewable resources, which also serve as better replacements for petroleum-based products. More attention has been given to these materials because of their low density and high mechanical, renewable, and biodegradable properties. There are many works in the literature on the isolation of NFC and CNC from different sources like hard/soft wood and agriculture biomass. However, this is a comprehensive review dedicated to the properties of NFC and CNC extracted only from agriculture and industrial waste using mechanical, chemical, and enzymatic methods. This article explores in detail the importance of agriculture waste and pretreatments, methods involved in the production of nanocellulose, and the properties of NC prepared from crop and industrial wastes. The potential applications of nanocellulose from different sources are discussed. The current extensive industrial activities in the production of nanocellulose are presented. This review will likely draw the attention of researchers toward crop and industrial wastes as a new source in the realm of nanocellulose.

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The crystallization behavior and the crystalline structure of nylon6-clay nanocomposites are investigated with regard to the processing conditions and thermal treatment. Microextruded bulk samples as well as blown films are under concern. The often reported nucleating effect of the clay particles is shown to strongly depend on the processing parameters prior to the solidification step, namely, the shear intensity which promotes self-nucleation and the temperature of the melt which regulates the density of these unstable nuclei. The MMT content influences the crystallization kinetics and the crystalline structure via the shear amplification phenomenon which increases the densities of both the shear-induced and the MMT-induced nuclei. The MMT platelets also turned out to hinder the crystal growth. The cooling rate plays a major role on the final crystalline structure by shifting the crystallization temperature in the specific growth range of either the Ror the γ-crystal forms of the nylon6 matrix. Blown films corroborate the findings from microextruded samples regarding the competition between nucleation and growth in the resulting crystalline form of the nylon6 matrix. Besides, the strong texturing of the nanocomposite films provides information on the local arrangement of the chains and crystal unit cell on the MMT platelets.