Crystal growth rates of spherulites of P-phase poly(propy1ene)s and of an ethylene/propene block copolymer, crystallized from the melt, have been investigated in the temperature range of 122 to 146 "C. On the basis of the regime theory, a transition between regime I1 and I11 is found at A T = 37-43.5 K. The nucleation constant for pphase poly@ropylene) based on the current theory of crystal growth was determined, and the fold surface free energy of /3-phase poly(propy1ene) was estimated from the nucleation constant for different samples to lie between 48,2 and 55,2 erg/cm2 (1 erg = J).

No abstract

No abstract

No abstract

No abstract

No abstract

Dynamic assemblies of π-conjugated bispyridinium guests with cucurbit[8]uril in aqueous solution could be distinguished by real-time naked-eye observation of the resulting quantitative fluorescence emissions.

Poly­(ethylene imine) (PEI) is a cationic polymer that is commercially available in linear PEI (LPEI) and branched PEI (BPEI) architectures for both biological and environmental applications. When the LPEI or BPEI is coupled with divinyl sulfone, cross-linked PEI is formed, and it has been researched for its same robust properties as traditional PEI, but it has a rigid, insoluble structure. Herein, we present the first direct comparison of cross-linked linear PEI microgels and branched PEI microgels (LPM and BPM, respectively) for both their intrinsic characteristics, such as morphology, surface charge, and surface chemistry, and their applications in antimicrobial activity, copper chelation, and CO2 capture. The Cu­(II) adsorption capacity of the LPMs is larger than their branched counterparts, and their performance is comparable to that of similar materials with a maximum adsorption capacity of 86.8 mg/g. LPM and BPM shows no significant inhibition in bacterial growth compared to a positive control (culture inoculated with bacteria and no PEI treatment) while the PEI precursors all show complete inhibition of growth. The LPMs were found to be good CO2 adsorbents compared to the BPMs, which adsorbed and desorbed CO2 immediately. The best performing LPM has an adsorption capacity of 4.34 mmol/g at 1 bar CO2. In summary, we have described the first pro-environmental PEI gels, which function as a well-performing dry CO2 adsorbent and copper-chelating agent that is benign to bacteria.