Day: November 15, 2022

Christmann, Julien published the artcilePhotostabilization of polyethylene by a hindered amine light stabilizer in blooming conditions and impact of MDO processing, HPLC of Formula: 52829-07-9, the main research area is polyethylene light stabilizer MDO processing photostabilization property.

The effect of machine direction orientation (MDO) processing on the photostabilization of LLDPE samples containing Tinuvin 770 was studied. The amount of Tinuvin 770 in the processed samples was deliberately chosen at a level higher than the reported solubility at ambient temperature for two main reasons: the first reason was to assess the equilibrium between the soluble and nonsol. forms of this additive and the impact of the MDO process, and the second was to demonstrate the role of a higher temperature in accelerated artificial photoaging on the protective role played by the nonsol. part. The results reported in this article show that at room temperature, a nonnegligible amount of Tinuvin 770 precipitates at the surface, which is commonly termed blooming. However, the additive that bloomed at the surface can be dissolved within the polymer with increasing temperature, which is the case in the conditions of accelerated artificial photoaging but not the case of natural outdoor weathering. Such phys. phenomena are responsible for a possible bias brought by temperature during accelerated photoaging, which can affect aging tests. This questions the representativeness of accelerated aging at higher temperatures for polymers containing a blooming stabilizer.

Polymer Degradation and Stability published new progress about Aging of materials, accelerated. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, HPLC of Formula: 52829-07-9.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Slouf, Miroslav published the artcileProoxidant activity of phenolic stabilizers in polyolefins during accelerated photooxidation, Recommanded Product: Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, the main research area is prooxidant phenolic stabilizer polyolefin accelerated photooxidation.

Polymer plaques made of high d. polyethylene (HDPE) and of two types of cycloolefin copolymer (COC) differing in glass transition temperature, were stabilized with 0.2 or 1.0 weight % of natural (α-tocopherol) or synthetic (Irganox 1010) phenolic stabilizer or hindered amine stabilizer (Tinuvin 770) and aged using accelerated weathering technique (WOM). The efficiency of the phenolic stabilizers was compared among themselves and with well-established Tinuvin770. Concentration profiles of radicals generated inside polymer plaques during WOM exposure were determined by ESRI, profiles of oxidation products and crystallinity inside the HDPE plaques were determined by IR microspectroscopy, oxidation products in COC copolymers were identified using ATR, the changes of local mech. properties of the polymer plaques were characterized using microindentation hardness testing, and their morphol. was studied by light and/or SEM. All the techniques evidenced high stability of neat COC against photooxidation processes, whereas neat HDPE exhibited fast photooxidation of the surface layers. Tinuvin770 was found to provide long term protection to both HDPE and COC against photodegradation In contrast, the same polymers stabilized with the natural phenolic antioxidant α-tocopherol (the most active component of vitamin E) or synthetic phenolic antioxidant Irganox1010 exhibited an increase in the surface oxidation in comparison with the neat polymers during WOM exposure, proving prooxidant activity of phenolic stabilizers during WOM exposure in all polymers studied. The prooxidant activity α-tocopherol was stronger in comparison with Irganox1010. We conclude that neither of the two phenolic stabilizers was able to provide long term protection of the investigated polymers against photooxidation

Polymer Degradation and Stability published new progress about Aging of materials, accelerated. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, Recommanded Product: Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Desai, Umang published the artcileA comparison of evolution of adhesion mechanisms and strength post damp-heat aging for a range of VA content in EVA encapsulant with photovoltaic backsheet, Application In Synthesis of 52829-07-9, the main research area is ethylene vinyl acetate film fabrication adhesion strength.

Ethylene vinyl acetate (EVA) is an effective encapsulant to adhere various layers in the photovoltaic (PV) module. In this study, we have fabricated EVA films containing different vinyl acetate (VA) content (18%, 24%, 33% and 40%) and laminated between two layers of backsheet (BS). These laminates have been subjected to damp-heat (DH) ageing at 85OC and 85% relative humidity (RH) for 1000 h to evaluate the change in adhesion strength at EVA/BS interface using the T-peel test. The adhesion strength for EVA containing 18% VA content has been found to improve but it deteriorates for EVA with 33 and 40% VA content after ageing. However, adhesion strength for EVA containing 24% VA content is found unaffected after ageing. The degree of crosslinking and VA content have been determined through gel content measurement and thermo-gravimetric anal. (TGA) resp. The degree of crosslinking and VA content increases significantly in EVA18 but decreases in EVA40 due to DH ageing. The chem. changes have been examined by the Fourier transform IR spectroscopy (FTIR) and the XPS. The failure mode (cohesive or delamination) at the interface and its correlation with the adhesion strength has been explored using XPS. The failure mode at the EVA18/BS interface alters from delamination type in pristine condition to the cohesive type due to DH ageing. However, the failure mode for EVA24 and EVA40 is found to be cohesive in both the pristine and aged condition.

Solar Energy published new progress about Adhesion, physical, interfacial. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, Application In Synthesis of 52829-07-9.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Freifelder, Morris published the artcileNuclear magnetic resonance spectra of some N-substituted methylamines. II. Effect of acidic conditions, Quality Control of 1690-74-0, the main research area is .

cf. CA 64, 4478f. The N.M.R. spectra of a number of N-substituted methylamines in acidic media are examined Among those studied–RNHCH3 (R is alkyl, aralkyl, cyclic, or cycloalkyl)–the N-methyl signal is a triplet (J = 5.5 cps.) when the spectra are run in various solvents to which hydrochloric acid is added to pH 1.0 or below. Under similar conditions, the spectra of tertiary N-methylamines, where one of the above R groups is substituted for H, show the N-methyl signal as a doublet (J = 4-5.5 cps.). Splitting of the signal among saturated N-methyl heterocycles is observed in strongly acidified solvent only when one N atom is part of the heterocyclic system. In neutral solvent, the spectra of the aforementioned compounds show a single peak for the N-methyl protons in every instance. In the piperazine series, if one ring N is acylated and the spectrum of the 1-acyl-4-methylpiperazine is ran in trifluoroacetic acid, the N-methyl signal is seen as a doublet, otherwise a single peak is noted among other N-methylpiperazines. An attempt is made to classify N-substituted methylamines by means of the N-methyl signal in their spectra in neutral solvent and various acidic media.

Journal of Organic Chemistry published new progress about NMR (nuclear magnetic resonance). 1690-74-0 belongs to class piperidines, name is Methyl 1-methylpiperidine-2-carboxylate, and the molecular formula is C8H15NO2, Quality Control of 1690-74-0.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem