The melt drawability including melt strength (MS) and stretching ratio (V) of the neat low-density polyethylene (LDPE) and the LDPE composites loaded with a nanometer zinc oxide (nano-ZnO) were measured using a melt spinning method in capillary extruding temperature varied from 160 to 200℃ and within capillary flow rate range from 9 to 36 mm/s. It was found that the stretching ratio of the neat LDPE and the LDPE/nano-ZnO composites reduced with an increase of capillary flow rate while the V added with in a rise of capillary temperature. The melt strength of the neat LDPE and the LDPE/nano-ZnO composites enlarged with raising capillary flow speed; the MS reduced with an addition of capillary temperature. In addition, the dependence of the MS of the composites on the capillary temperature approximately accorded the Arrhenius expression.

Elastomeric nano-particles (ENPs) have been used widely and nano-scale effects have been found when used in polymer modification. For example, ENPs could increase toughness and heat resistance of plastics simultaneously when blending ENPs with plastics. Anomalies have also been found when ENPs were used in rubber modification, thermoplastic vulcanizates (TPVs) preparation and assisting dispersion of other nano-particles and ultra-fine additives in polymer matrix. The preparation, nano-scale effect and applications of the ENPs will be reviewed in this feature article.

Bio-plastics have gained tremendous attention, due to the increasing environmental pressure on global warming and plastic pollution. Among them, poly (lactic acid) (PLA) is both bio-based and bio-degradable, which has been widely used in many disposable packaging applications. The global market for PLA demand doubles every 3-4 years, as estimated by Jem's law.

Compared to traditional petroleum-based plastics, PLA is more expensive and usually has less mechanical and physical properties. The recent compounding efforts and the commercialization of D(−) lactic acid and its polymer PDLA have the potential to improve the mechanical and thermal characteristics of PLA (e.g. by forming stereocomplex PLA) for applications in high-end markets. However, the usage of PLA in some other applications is still limited.

With a structure similar to PLA, poly (glycolic acid) (PGA) has promising characteristics such as good biodegradability and barrier properties, which is potentially a beneficial supplement to PLA. The modification of PLA with PGA can be achieved via co-polymerization, physical blending and multilayer lamination. PGA and its combination with PLA have been widely studied in bio-medical applications, but not been well developed at large scales due to its relatively high production cost. In this case, the development of novel production technology and the advent of government regulations are the key drivers for the global transition towards bioplastics. Recently, multiple governmental regulations have been released that restrict the use of traditional plastics and facilitate bio-degradable plastic applications. PGA can be derived from industrial waste gases using an innovative production technology, which reduces carbon emissions and its production cost. By developing the production and compounding technology, PGA can be combined with PLA to play an essential role for a sustainable and environmental friendly plastic industry, especially for single-used products requiring fast degradation at room temperature or in the nature environment.

Amino celluloses are semisynthetic polysaccharide derivatives that are functionalized with amino groups. This class of bio-based polymers has a number of interesting properties for advanced applications such as potential antimicrobial activity and pronounced surface affinity towards various materials. Herein, the synthesis of a novel type of 6-deoxy-6-amino cellulose derivatives with a polar and highly branched substituent (2-amino-2-(hydroxymethyl)propane-1,3-diol/TRIS) is described for the first time. Fundamental principles for the synthesis by nucleophilic displacement of tosylated intermediates are highlighted, thus, providing access to materials with well-defined molecular structures. TRIS-functionalized cellulose derivatives with degrees of substitution (DS) of up to 0.5 were obtained. The solubility and rheological properties of the products showed a strong dependence on the pH value. Due to the unique structural features of the substituent, TRIS amino cellulose derivatives possess a high application potential.

Effects of various geometrical and physical factors, as well as the method of data reduction (analysis of experimental force–displacement curves) on the values of local interfacial strength parameters (local IFSS, τ_d, and critical energy release rate, G_ic) determined by means of a single fiber pull-out test are discussed. Experimental results of our pull-out tests on several fiber–polymer matrix systems showed that τ_d and G_ic weakly depended on geometrical factors. However, the pull-out test appeared to be sensitive to the conditions of specimen formation and testing, such as changing the nature of the contacting surfaces (fiber sizing) and the fiber pull-out rate. Of several methods of τ_d and G_ic determination from a force–displacement curve, the most reliable and reproducible one is the approach based on the values of the maximum force recorded in a pull-out test and the interfacial frictional force immediately after fiber debonding.

The review deals with the reasons for the drastic difference between the theoretically derived expectations regarding the mechanical properties of polymer nanocomposites and the experimentally obtained results. It is assumed that the most probable reason is the fact that we hardly deal with true nanocomposites because in the composites prepared via blending of polymer matrix with the reinforcing nano-size material the reinforcing elements are not the single nanoparticles but their aggregates with sizes in the micrometer range. This situation is due to the fact that currently there are not effective techniques for proper dispersion of nanomaterials into polymer matrix. The solution suggested is in avoiding the dispersion step in the composite preparation as the “concept of converting instead of adding” does. Two examples of true polymer nanocomposites – the nanofibrillar polymer–polymer and the nanofibrillar single polymer composites – are described.