Influence of carbon black type and concentration upon thermooxidation of the amorphous phase in high and low density polyethylenes

Abstract

Thermooxidation in solid and molten state of HDPE and LDPE loaded with different types of carbon black is studied by DSC measurements on mill rolled specimens and tensile test on compression moulded specimens by considering the isothermal induction times a t 210 to 25OOC and the elongation a t break a t room temperature, respectively. The terms of morphology stability and compatibility between P E and carbon black species are defined on the basis of recently established topoenergetic principles according t o which the notions have meaning only in respect t o a transformation process revealed in a measuring system which includes the standard experimental conditions. The universal representation allows to determine by iteration the threshold temperature To = (240 f 10) K below which the thermooxidation of the amorphous phase is practically inhibited. This value fairly corresponds to the glass transition temperature like for other polymers and transformation processes studied on topoenergetic basis. Der EinfluP von Art und Konzentration des RuPes auf die Thermooxidation der amorphen Phase in Polyethylenen hoher und niedriger DichteDie Thermooxidation von mit verschiedenen RuBtypen gefullten HDPE und LDPE im festen und geschmolzenen Zustand wurde mittels DSC-Messungen an gewalzten Proben und durch Zugprufungen an gepreBten Proben untersucht, indem die isothermen Induktionspcrioden im Bereich von 210 bis 250°C sowie die Bruchdehnungen bei Raumtemperatur bestimmt wurden. Die Begriffe der morphologischen Stabilitat und der Vertraglichkeit zwischen PE und RUB werden auf der Basis von in neueren Arbeiten abgeleiteten topoenergetischen Prinzipien definiert. Danach haben diese Begriffe einen Sinn nur in bezug auf den TransformationsprozeB in einem bestimmten MelJsystem, wozu auch die experimentellen Standardbedingungen rnit gehoren. Die universelle Darstellung erlaubt die Bestimmung einer Grenztemperatur T o = (240 & 10) K, unterhalb der praktisch keine Thermooxidation der amorphen Phase erfolgt. Dieser Wert stimmt ziemlich gut rnit der Glasubergangstemperatur uberein, wie das auch bei anderen Polymeren und Transforrnationsprozessen bei der Untersuchung auf topoenergetischer Basis gefunden wurde. Bnuxnue muna u Eonyenmpayuu caMu na mepwoomcnenue awopg5nod 6a3bc nonusmunena ebacolcoii u nu3lcoiL nhomnocmu

Polyelectrolyte complexes. VI. Polycation structure, polyanion molar mass, and polyion concentration effects on complex nanoparticles based on poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate)

“…Interpolyelectrolyte complexes (IPECs) with different structures and properties (stoichiometric [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] or nonstoichiometric [17][18][19][20][21][22][23][24][25][26][27][28] ) can result from a very fast, ionic exchange reaction between two oppositely charged polyelectrolytes, accompanied by the release of the corresponding small counterions, leading to the increase of the system entropy and to the complex stability. Nonstoichiometric IPECs (NIPECs) have been obtained mainly when the complementary polyelectrolytes have significantly different molar masses, nonstoichiometric systems and dilute aqueous solutions, 3,4,18 -23 structural differences between oppositely charged polyions, and the presence of low amounts of NaCl being also necessary to obtain soluble NIPECs.…”

Comparative study on molecular associations in solid and liquid phases of aqueous solutions. I. Presentation of high resolution mixing calorimetry, differential scanning calorimetry, dynamic thermal densimetry, and thermomechanical analysis

“…These coherent precipitates inside the crystalline domains even for polycrystalline materials (in which the exterior amorphous domain usually has another structure) are responsible for specific order-disorder transitions more or less distinct from the ones proper to pure crystalline fragments. The calorimetric behaviour of pure water [5], single crystals in the series SnCl,(H,O),(D,O),_, r16, 171, polyethylenes with grafted crystalline defects [20,[21][22][23][24], and trioxane-dioxolane copolymers containing crystallizing and non-crystallizing chain units [26], are some representative cases which strongly argue the experiments on melting behaviour of the aqueous solutions. On the other hand, the calorimetric measuring systems represent a variation on a string" among the analytical techniques, because any kind of transformation process is accompanied by a caloric flow, so t h a t its kinetics can well be studied in an adequate calorimetric disposition [12-151. According t o the above mentioned conclusions it is compulsory t o apply a reproducible thermal cycle for all test specimens in view to compare their melting behaviour.…”