Polyolefin graft copolymers through a ring-opening metathesis grafting through approach

A series of polyethylene-g-atactic polypropylene graft copolymers were synthesized by grafting through copolymerization of a cyclooctene terminated aPP macromonomer with cyclooctene monomer and subsequent hydrogenation.

On the Combined Effect of Both the Reinforcement and a Waste Based Interfacial Modifier on the Matrix Glass Transition in iPP/a-PP-pPBMA/Mica Composites

This work deals with the changes of the glass transition temperature (Tg) of the polymer in polypropylene/mica composites due to the combined and synergistic effect of the reinforcement and the interfacial modifier. In our case, we studied the effect on Tg of platy mica and an interfacial modifier with p-phenylen-bis-maleamic acid (pPBMA) grafted groups onto atactic polypropylene (aPP-pPBMA). This one contains 5.0 × 10−4 g·mol−1 (15% w/w) grafted pPBMA and was previously obtained by the author’s labs by using industrial polymerization wastes (aPP). The objective of the article must be perceived as two-fold. On one hand, the determination of the changes in the glass transition temperature of the isotactic polypropylene phase (iPP) due to both the reinforcement and the agent as determined form the damp factor in DMA analysis. On the other hand, forecasting the variation of this parameter (Tg) as a function of both the interfacial agent and reinforcement content. For such purposes, and by assuming the complex character of the iPP/aPP-pPBMA/Mica system, wherein interaction between the components will define the final behaviour, a Box–Wilson experimental design considering the amount of mica particles and of interface agent as the independent variables, and the Tg as the dependent one, has been used. By taking in mind that the glass transition is a design threshold for the ultimate properties of parts based in this type of organic–inorganic hybrid materials, the final purpose of the work is the prediction and interpretation of the effect of both variables on this key parameter.

POLYMER ADDITIVE EFFECT ON THE STRUCTURAL AND MECHANICAL PROPERTIES OF THE ORGANIC PART OF OIL BITUMINOUS ROCK

The article presents the results of gas chromatographic analysis method of the organic part of oil bituminous rock and the results from the analysis of the molecular weight distribution of atactic polypropylene carried out using reverse gel-permeation chromatography. The research results of the structural and mechanical properties of the bitumen part of oil bituminous rock (OBR) of the Iman-Kara deposit, atactic polypropylene (APP) and compositions based on them, carried out on the instrument Reotest 2.1, are also presented herein. It has been determined that the organic part of OBR of the Iman-Kara deposit mainly consists of oxygen-containing organic compounds with additions of heteroatomic structures (sulfur, haloids and nitrogen) with a weight fraction of 53.97%. According to the chromatogram of the molecularly-mass distributed atactic polypropylene, it is found that the average time of fraction maximum yield is 11.4 minutes, the corresponding value of logarithm of the average molecular weight Lg(M) equals to 5.5. Accordingly, the average molecular weight of fraction M is 400. The change patterns of the rheological properties of the organic part of OBR, atactic polypropylene and compositions based on them are described. It has been established that the addition of APP to the organic part of OBR creates a disperse system in which the particles of a polymer additive that are swollen due to oily components are dispersed in the bitumen medium. At the same time, mechanical properties such as elasticity and heat resistance of the organic part of oil bituminous rock are improved. These properties can be shown only with the optimum quantity of APP, when their concentration is such that they form an uninterrupted net structure. The influence patterns of APP on the structure of the organic part of OBR defined in the process of experiments can also be used in further experiments during development of various types of waterproofing materials and coatings.

The Role of a Succinyl Fluorescein-Succinic Anhydride Grafted Atactic Polypropylene on the Dynamic Mechanical Properties of Polypropylene/Polyamide-6 Blends at the Polypropylene Glass Transition

The present article adequately supports a twofold objective. On one hand, the study of the dynamic mechanical behavior of polypropylene/polyamide-6 blends modified by a novel compatibilizer was the objective. This was previously obtained by chemical modification of an atactic polypropylene polymerization waste. On the other hand, the accurate predictions of these properties in the experimental space scanned was the objective. As a novelty, this compatibilizer contains grafts rather than just maleated ones. Therefore, it consists precisely of an atactic polymer containing succinic anhydride (SA) bridges and both backbone and terminal grafted succinyl-fluorescein groups (SFSA) attached to the atactic backbone (aPP-SFSA). Therefore, it contains 6.2% of total grafting (2.5% as SA and 3.7% as SF), which is equivalent to 6.2 × 10−4 g·mol−1. This interfacial agent was uniquely designed and obtained by the authors themselves. Essentially, this article focuses on how the beneficial effect of both PA6 and aPP-SFSA varies the elastic (E’) and the viscous (E’’) behavior of the iPP/aPP-SFSA/PA6 blend at the iPP glass transition. Thus, we accurately measured the Dynamic Mechanical Analysis (DMA) parameters (E’, E’’) at this specific point considering it represents an extremely unfavorable scenario for the interfacial modifier due to mobility restrictions. Hence, this evidences the real interfacial modifications caused by aPP-SFSA to the iPP/PA6 system. Even more, and since each of the necessary components in the blend typically interacts with one another, we employed a Box–Wilson experimental design by its marked resemblance to the “agent-based models”. In this manner, we obtained complex algorithms accurately forecasting the dynamic mechanical behavior of the blends for all the composition range of the iPP/aPP-SFSA/PA6 system at the glass transition of iPP.

New Test Method for Measuring Reflective Cracking in Hot-Mix Asphalt Overlay Pavements

Reflective cracking is a common distress in hot-mix asphalt (HMA) overlay. A test method that can provide comprehensive information about reflective cracking is thus needed. In this study, an apparatus named Joint Motion Simulation System (JMSS) was developed, which consists of two hydraulic servo-systems and a temperature chamber. A newly developed reflective cracking test method (NRCTM) based on JMSS was proposed, which is applicable for airport pavement. This method considers the influences of both traffic and thermal loads under controlled temperature conditions. Laboratory tests were conducted to verify both repeatability and sensitivity of the NRCTM. The tests results revealed a coefficient of variation that was lower than 13%, indicating that the NRCTM exhibited satisfactory repeatability. In addition, the method was sensitive to four factors: test temperature, combination of loads, compaction of specimen, and type of mixture. Moreover, three types of interlayer structures were evaluated with the NRCTM: geotextile, stress-absorbing layers, and atactic polypropylene modified linoleum. The geotextile performed better than the other two interlayer systems. Thus, the NRCTM can be used for measuring the reflective cracking in HMA overlay with acceptable repeatability and sensitivity.