An improved theoretical model of copolymer reshuffling by end-group interchange reactions is presented. It can be applied to describe the evolution of the copolymer structure not only in polymer melts, as proposed in the commented paper, but also in polymer solutions, which is more common in laboratory experiments.

The averages for the cross-linking of distributions with different functional groups were studied. One application is the step growth polymerization of type A₂ + B₂ where a branching agent is introduced in the form of a monomer A_f with 3 or more functional groups instead of 2. The functionality of the branching agent f = 3, 4‥7 has practically no effect on the weight average but on the z-average; the ratio DP_z/DP_w is linear in the branching density and functionality of the branching agent.

A dissipative particle dynamics (DPD) method is established to systematically simulate the dynamic behavior of polymer chains and the properties of the polymer solution in microchannels by combining the modified FENE chain model and a new boundary condition setting, especially for the gradually contracted microchannel.

The isoconversional state diagram (ISD) method is a graphical representation of the model free kinetics (MFK) method. Both can make kinetic predictions of the same quality if the experimental data is free of random error. However, as soon as the input data contains random errors, the ISD method outperforms the MFK method due to its unique correction procedure.

The meshing region of screws undergoes the most severe wear, mainly due to the combined effect of shear forces and contact stress. Tribological tests carried out using a plate-on-disc tribometer show that the incorporation of cellulose with higher aspect ratios leads to a decrease in friction coefficients, resulting in the formation of an orientation transfer layer on the contact surface.

Interfacial thermal resistance (ITR) in polymer–polymer interfaces is experimentally measured in this paper by the multi-layered bulk sample approach. Based on numerical simulation and experimental verification, new techniques of layer-overlapping samples are developed. ITR test shows a linear increase with the increase of layer number, and specific ITR for PP-HDPE and PLA-HDPE are reported.