SYNTHESIS OF HETEROARM STAR-SHAPED POLYMER BY THE USE OF POLYFUNCTIONAL CHAIN-TRANSFER AGENT via CONVENTIONAL FREE RADICAL POLYMERIZATION

Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methacrylate was carried out in the presence of a polyfunctional chain transfer agent,pentaerythritol tetrakis(3-mercaptopropinate).At appropriate monomer conversions,two-arm PMMA having two residual thiol groups at the chain center or three-arm PMMA having one residual thiol group at the core were o...

Synthesis, Crystal Structure and Luminescent Property of Ladder-shaped Zinc Coordination Polymer with Mixed Polyfunctional Ligands

One new Zn（Ⅱ） complex [Zn2（cptpy）2（tzba）（H2O）]·H2O（1, Hcptpy = 4-（4-carboxyphenyl）-2,2＇：4＇,4＇＇-terpyridine（Hcptpy）, H_2tzba = 4-（tetrazol-5-yl）benzenecarboxylic acid） has been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction techniques. It is formulated as C52H36O8N10Zn2, crystallizes in monoclinic system, space group P21/c with α = 15.1599（13）, b = 28.083（2）, c = 10.9039（9） A, b = 97.517（8）o. V = 4602.3（6） A^3, Z = 4, Mr = 1059.68, Dc = 1.529 g/cm^3, F（000） = 2168 and μ = 1.112 mm^-1. The final R = 0.0831 and wR = 0.2143 for 8458 observed reflections with I 〉 2s（I）. The assembly of polyfunctional organic ligands Hcptpy and H_2tzba with Zn（II） atoms resulting in a rare example of double-edge ladders, which is further extended into a 3D supramolecular network via O–H…O/N hydrogen bonds. In addition, thermal gravimetric analysis（TGA） and PXRD patterns for 1 were studied. Photo luminescent property of 1 was also investigated.

Comparative Study on Dyeing of Cotton, Modal and Lyocell Fabrics Using Bifunctional and Polyfunctional Reactive Dyes

Polyfunctional reactive dyes have been introduced by the renowned dye manufacturers in the recent years for better exhaustion and fixation performance. This paper deals with evaluation of the dyeing performance of three cellulosic fibres namely cotton, modal and lyocell with polyfunctional (Avitera Cardinal SE) reactive dye in comparison a bifunctional-(Novacron Brilliant Red FN-3GL) reactive dye. The purpose of this study is to achieve a better understanding of exhaustion and fixation behaviour in dyeing of cotton, modal and lyocell fibres using these two types of reactive dyes. The dyeing was carried out at four different shade% (1%, 2%, 3%, and 4%). Besides studying exhaustion (%) and fixation (%) along with K/S values of dyed fabrics, several other quality parameters e.g. bursting strength, pilling resistance and colour fastness to wash were also examined. Finally, the optimum combination among the three types of cellulosic fabrics and two types of reactive dyes was observed. Lyocell fabric and polyfunctional reactive dyes have been found more sustainable.

Influence of Rheological Active Additives on the Properties of Self-compacting Concrete

The effect of rheological-active additives on the properties of cement suspensions and self-compacting concrete mixtures have been studied.In order to increase the rheological matrix and provide high fluidity,stone powders were used during the crushing of local mountain rocks in self-compacting concrete.Taking into account the high dispersion of rheological-active additives,highly effective plasticizers were used to regulate the reotechnological properties of cement-based mixtures.The effect of sulfonaphthalen-formaldehyde oligomer and polycarboxylate-based hyperplasticizer on rheological properties of cement systems as plasticized additive on methodology proposed by V Kalashnikov was evaluated.The flow rate of cement suspension is determined by means of mini-viscosimeter,spreading of cement-sand mortar by means of Hegermann cone,and the slump of concrete mixture by means of Abraham’s cone.On the basis of obtained results,it was determined that limestone powder was more efficient than other stone powders.Thus,when adding 40%limestone powder to the mixture,the compressive strength of the samples taken from self-compacting concrete mixture increases by 15%-30%compared to the control samples.The optimal quantities of rheological-active additives and plasticizers have been identified and the possibility of obtaining high-strength self-compacting concrete based on them has been confirmed.

Trifunctionalization of Aryl Iodides with Two Distinct Nitrogen and Carbon Electrophiles by Palladium/Norbornene Catalysis

Main observation and conclusion Herein,we report a highly chemo-and regioselective vicinal trifunctionalization of aryl iodides by palladium/norbornene(Pd/NBE)catalysis.The key feature of this new method is the introduction of two distinct nitrogen and carbon electrophiles,with a large gap in reactivity,for ortho-unsubstituted aryl iodides via an intermolecular and intramolecular C―H functionalization,respectively.Eight types of ipso terminations can be coupled with both ortho-amination and ortho-alkylation,affording a variety of polysubstituted benzoheterocyclic scaffolds.Silicon-tethered substrates can lead to polyfucntional arenes via a single-step operation.Noteworthy,these products exhibit full-color-tunable strong fluorescence emissions with large Stokes shifts,and product 7r can serve as a fluorescent probe to specifically target lysosome in living cells.

Non-linear Radical Additions-Coupling Polymerization of Monovinyl Monomers towards Polymer Networks: Theory, Tunability and Heritable Architecture

Exploring new polymerization strategy for current available monomers is a big challenge in polymer science. Here we re-investigate radical polymerization of monovinyl monomer(MVM) initiated by uniform branched polyfunctional initiator(PFI), which is termed non-linear radical additions-coupling polymerization(NLRAs CP). In NLRAs CP, both addition and coupling reactions of radical contribute to the construction of the polymer chains, which leads to continuous growth of branch topology. Theoretical analysis of NLRAs CP predicts that the gelation is determined by the functionality of PFI(a), the extent of initiation of the PFI(q) and the termination factor of radical(φ). NLRAs CPs of styrene and methyl methacrylate promoted by Cu(0)/MeTREN or Mn_(2)(CO)_(10)/visible light were conducted. After the cleavage of incorporated PFI fragment or junctions in the network, the network was transformed to linear chains having almost the same structure as segmental chains in the precursor network. This allows the reverse deducing the network structure from its cleaved products. It has been proven that NLRAs CP includes stepwise initiation of PFI, chain-growth of segmental chains and successive endlinking of macroradicals derived from PFI. The three parameters related to the gelation process, a, q and φ, were adjusted via binary PFI, the feed ratio of [Mn_(2)(CO)_(10)]/[PFI] and addition of non-homopolymerizable comonomer respectively. The minimum values of a and q, and the minimum amount of comonomer required for gelation were determined,which can be applied to estimate φ of various macroradicals. NLRAs CP opens a general and facile strategy for synthesis of a variety of polymer networks with heritable architecture by one-pot polymerization of various MVMs.