Термогравіметричний аналіз поліціанурат-поліуретанових прищеплених взаємопроникних сіток

Досліджена термоокиснювальна деструкція повних послідовних взаємопроникних сіток на основі поліціануратної сітки (ПЦ) та сітчастого поліуретану (СПУ). Завдяки хімічній взаємодії диціанового ефіру бісфенолу А (ДЦЕБА) з СПУ під час поліциклотримеризації ДЦЕБА в матриці СПУ можуть утворюватись прищеплені ВПС (ПВПС). Співіснування СПУ, ПЦ та гібридної сітки (ГС) у ПВПС потверджується наявністю стадій розкладу, характерних для кожної із структур. Частка СПУ, ПЦ та ГС у ПВПС залежить від співвідношення вихідних компонентів. Усі три структури присутні у 90/10 СПУ/ПЦ; ГС та ПЦ спостерігали у 70/30 ПВПС, а гібридна сітка виявилась основною структурою, зафіксованою у 50/50 ПВПС

Effect of Gamma-Irradiated Recycled Low-Density Polyethylene on the High- and Low-Temperature Properties of Bitumen

This paper describes polymer modification of bitumen with gamma-irradiated recycled (γ-LDPER) low-density polyethylene. The recycled low-density polyethylene (LDPER) was obtained from greenhouse films exposed to sunlight at least one year. The surface of the LDPER was treated by gamma beam irradiation that provided formation of free radicals and some functional groups that may contribute to the creation of strong chemical bonds between polymer modifier and bitumen. Five different samples of bitumen/γ-LDPER compositions with the modifier content, wt. %: 1, 3, 5, 7 and 9, were prepared. The effects of the γ-LDPER on original and aged bitumen were investigated by means of morphological, chemical, and physical testing program, including FTIR spectroscopy, conventional tests, rotational viscosity (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests. Superior performing asphalt pavements (Superpave) specifications were used to analyze mechanical test results as well as to determine the performance grades (PG) of the binders. Optimum usage of the γ-LDPER as modifier in bitumen were suggested after testing program. The results reveal the stiffening effect of the γ-LDPER on bitumen that provide enhanced temperature susceptibility and also promise better performance grades (PG) with γ-LDPER polymer modification

Degradation of non-vulcanized natural rubber - renewable resource for fine chemicals used in polymer synthesis

In the current scenario, there is growing interest in the products of degradation of rubber (natural and synthetic) for specific applications in different industry sectors, whose benefits in replacing conventionally used products are mainly related to sustainability. Since the degradation products of rubber can be used in different areas, several research groups may have the interest aroused by these products, but are not familiar with the aspects related to the chemical behavior of rubber. This review aims to bring together the key information in the published literature on the degradation of natural rubber, emphasizing metatheses reactions, oxidative damage and splitting of the double bond, in order to serve as a reference source for researchers from different fields interested in obtaining such kind of products. The structures and properties as well as additional chemical transformations resulting in oligomers of isoprene, functionalised oligomers and polymers based on both are also described

Синтез нанопористих поліціаноуретанових плівок in situ з іонними рідинами

Розроблено та охарактеризовано пористі плівкові матеріали на основі термостабільних поліціаноуретанів, одержаних поліциклотримеризацією диціанових естерів бісфенолу Е in situ з 1-гептилпіримідин тетрафлуороборатом, [HPyr][BF4], іонною рідиною (ІР) з подальшою простою екстракцією ІР. За допомогою сканувальної електронної мікроскопії та ДСК-термопорометрії підтверджено формування нанопористої структури в зразках ЦЕС. Встановлено, що розподіл пор за розмірами варіюється в діапазоні від ~20 до ~180 нм із середнім діаметром пор приблизно 45 і 60 нм, що залежить від початкового вмісту пороутворювача в досліджуваних зразках.The article discusses characteritics of novel porous film materials of thermostable polycyanurates generated by polycyclotrimerization of dicyanate ester of bisphenol E in situ of 1-heptylpyridinium tetrafluoroborate, [HPyr][BF4], ionic liquid (IL) followed by simple extraction of IL. The scanning electron microscopy and DSC-based thermoporometry analyses confirmed the formation of the nanoporous structure in the investigated CER samples. The pore size distribution varied from ~20 to ~180 nm with an average pore diameter of around 45 and 60 nm depending on the initial porogen content in the studied CERs

Versatile approach to nanoporous polymers with bicontinuous morphology using metal templated synthesis

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Effect of Amino-Functionalized Polyhedral Oligomeric Silsesquioxanes on Structure-Property Relationships of Thermostable Hybrid Cyanate Ester Resin Based Nanocomposites

International audienceNanocomposites of cyanate ester resin (CER) filled with three different reactive aminofunctionalized polyhedral oligomeric silsesquioxane (POSS) were synthesized and characterized. The addition of a small quantity (0.1 wt.%) of amino-POSS chemically grafted to the CER network led to the increasing thermal stability of the CER matrix by 12-15 • C, depending on the type of amino-POSS. A significant increase of the glass transition temperature, T g (DSC data), and the temperature of α relaxation, T α (DMTA data), by 45-55 • C of the CER matrix with loading of nanofillers was evidenced. CER/POSS films exhibited a higher storage modulus than that of neat CER in the temperature range investigated. It was evidenced that CER/aminopropylisobutyl (APIB)-POSS, CER/N-phenylaminopropyl (NPAP)-POSS, and CER/aminoethyl aminopropylisobutyl (AEAPIB)-POSS nanocomposites induced a more homogenous α relaxation phenomenon with higher T α values and an enhanced nanocomposite elastic behavior. The value of the storage modulus, E , at 25 • C increased from 2.72 GPa for the pure CER matrix to 2.99-3.24 GPa for the nanocomposites with aminofunctionalized POSS nanoparticles. Furthermore, CER/amino-POSS nanocomposites possessed a higher specific surface area, gas permeability (CO 2 , He), and diffusion coefficients (CO 2) values than those for neat CER, due to an increasing free volume of the nanocomposites studied that is very important for their gas transport properties. Permeability grew by about 2 (He) and 3.5-4 times (CO 2), respectively, and the diffusion coefficient of CO 2 increased approximately twice for CER/amino-POSS nanocomposites in comparison with the neat CER network. The efficiency of amino-functionalized POSS in improving the thermal and transport properties of the CER/amino-POSS nanocomposites increased in a raw of reactive POSS containing one primary (APIB-POSS) < eight secondary (NPAP-POSS) < one secondary and one primary (AEAPIB-POSS) amino groups. APIB-POSS had the least strongly pronounced effect, since it could form covalent bonds with the CER network only by a reaction of one-NH 2 group, while AEAPIB-POSS displayed the most highly marked effect, since it could easily be incorporated into the CER network via a reaction of-NH 2 and-NH-groups with-O-C≡N groups from CER