The structure, morphology and thermal properties of biobased and biodegradable poly(butylene succinate-ran-butylene azelate) random copolyesters with a wide composition range were studied. These PBS-ran-PBAz copolymers can crystallize in the entire composition range despite being random, displaying a eutectic point when their melting point is plotted as a function of composition. Wide Angle Xray Scattering (WAXS) studies confirmed isodimorphic behavior where PBS-rich copolymers crystallize with PBS type unit cells with some PBAz repeating units inclusions and vice versa for PBAz-rich copolymers. Away from eutectic compositions the copolymers exhibit only one crystalline phase (PBS-rich or PBAzrich crystalline phases) while at the eutectic point both phases can crystallize. The only double crystalline copolymer amongst those prepared had a composition close to the eutectic point of 45 mol% PBS (and 55 mol% PBAz). The crystallization of the two phases occurred in the same temperature range upon cooling from the melt at 10ºC/min in a DSC (i.e., coincident crystallization). Self-nucleation (SN) studies of the PBS-rich phase were performed. After SN, the separate crystallization of each phase was clearly observed during cooling from the self-nucleation temperature (i.e., PBS and PBAz-rich phases). Small Angle X-ray Scattering (SAXS) experiments were performed for the first time for this type of isodimorphic copolymers. The results show that the lamellar long period is a strong function of composition. While limited inclusions of PBAz units within the crystal lattice only cause a slight expansion of the PBS component unit cell, the increase of comonomer content produces an unexpected synergistic increase in long periods and lamellar thickness values. In the case of the only double crystalline copolymer examined, the PBS-rich phase forms space filling spherulites (observed by Polarized Light Optical Microscopy, PLOM) at higher temperatures that template the superstructural morphology of the copolymer. These PBS-rich phase spherulites contain radial lamellar stacks whose long period was determined by SAXS. Upon further cooling, the PBAz-rich phase crystallizes in the intra-spherulitic amorphous regions with newly form lamellae that have their own distinct long period according to SAXS results. AFM observations of the PBS-rich crystalline lamellae confirmed the lamellar thickness and long spacings determined by SAXS. A schematic morphological model of the mixed spherulites produced by this double crystalline diblock copolymer is proposed based on the experimental evidences collected by SAXS, PLOM and AFM.

The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons.

Poly(lactic acid) (PLA) is one of the most promising alternatives for petrochemical-based plastics. Crystallization mediation provides the simplest and most practical approach for enhancing the properties of PLA. Here, recent advances in understanding the relationship between crystalline structure and properties of PLA are summarized. Methods for manipulating crystallization towards high-performance PLA materials are introduced.