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This paper discusses a novel approach that may provide a complete solution to combating oil spills. The technology is centered on a cross-linked polyolefin terpolymer (x−OS−DVB), containing 1-octene, styrene, and divinylbenzene units, which is an oil superabsorbent polymer (oil−SAP) with aliphatic and aromatic side chains that have similar solubility parameters (oleophilic and hydrophobic properties), with the hydrocarbons in crude oil. Some x−OS−DVB terpolymers, with desirable morphology (amorphous, low T g , and high free volume) and lightly cross-linked (complete network) structure, show rapid oil absorption and swelling to reach a capacity 45 times their weight. The capacity of oil uptake (swelling) is inversely proportional to the cross-linking density. The combination of selective oil absorption (without water) and tough mechanical strength offers buoyancy, stability, and easy recovery on water surfaces. The recovered oil-swelled gel, containing more than 98% oil and 2% x−OS−DVB, is suitable for regular oil-refining processes (an economic, no waste, and no pollutant approach). The bulk side chains in x−OS−DVB result in a relatively low ceiling temperature for depolymerization and zero heating residue at 450°C, well below the first distillation step (>600°C) in oil refining. Furthermore, polyolefins are the most inexpensive polymeric material, with a large production capability around the world. Overall, this cost-effective new polyolefin oil−SAP technology shall dramatically reduce the environmental impacts from oil spills and help recover one of our most precious natural resources.

A family of cross-linked polypropylene (x-PP) thin film dielectrics is systematically studied to understand the cross-linking effect on the dielectric properties. Evidently, the butylstyrene (BSt) cross-linkers increase both the dielectric constant (ε) and breakdown strength (E), without increasing energy loss. An x-PP dielectric, with 3.65 mol % BSt cross-linkers, exhibits a ε∼3, which is independent of a wide range of temperatures and frequencies, slim D-E hysteresis loops, high breakdown strength (E=650 MV/m), narrow breakdown distribution, and reliable energy storage capacity >5 J/cm3 (double that of state-of-the-art biaxially oriented polypropylene capacitors), without showing any increase in energy loss.

This paper discusses the synthesis of a new family of well-controlled isotactic polypropylene ionomers (iPP-NH 3 + Cl − ) containing up to 5 mol % of NH 3 + Cl − ionic groups, with high molecular weight and narrow molecular weight and composition distributions, as well as good processability in melt and solution. A systematic study was conducted using various isospecific Ziegler−Natta and metallocene catalysts in the copolymerization of propylene and a high α-olefin comonomer containing a silane-protected amino group and the subsequent work-up procedures that can prevent undesirable side reactions in forming iPP-NH 3 + Cl − ionomers in a one-pot process. The resulting copolymers were carefully monitored by polymer solubility and a combination of NMR, GPC-triple detectors, DSC, and mechanical property measurements. Evidently, the most suitable reaction process requires a combination of the rac-Me 2 Si[2-Me-4-Ph(Ind)] 2 ZrCl 2 metallocene catalyst system with a purified d-MAO (TMA-free), 6bis(trimethylsilyl)amino-1-hexene comonomer during the copolymerization reaction and a work-up procedure to directly interconvert the silane-protected amino groups (−N(SiMe 3 ) 2 ) into −NH 3 + Cl − ionic groups before exposing to air. The attempt of isolating both iPP-N(SiMe 3 ) 2 and iPP-NH 2 intermediates resulted in the insoluble (cross-linked) products. On the other hand, the resulting iPP-NH 3 + Cl − ionomers were melt processed in air and showed a systematic increase of mechanical properties and high-temperature stability with the increase of NH 3 + Cl − content.

We use simulations and experiments to delineate the mechanism by which the addition of a small number of polar −OH groups to a nonpolar polymer increases the static relative permittivity (or dielectric constant) by a factor of 2, but more importantly while keeping the dielectric loss in the frequency regime of interest to power electronics to less than 1%. Dielectric properties obtained from experiments on functionalized polyethylenes and polypropylenes as a function of −OH doping are in quantitative agreement with one another. Molecular dynamics simulations for the static relative permittivity of “dry” −OH functionalized polyethylene (in the absence of water) are apparently in quantitative agreement with experiments. However, these simulation results would further imply that there should be considerable dielectric loss beyond simulation time scales (>0.1 μs). Since there are minimal experimentally observed dielectric losses for times as short as a microsecond, we believe that a small amount of adsorbed water plays a critical role in this attenuated loss. We use simulations to derive the water concentration at saturation, and our results for this quantity are also in good agreement with experiments. Simulations of the static relative permittivity of PE–OH incorporating this quantity of hydration water are found to be in quantitative agreement with experiments when it is assumed that all the dipolar relaxations occur at time scales faster than 0.1 μs. These results suggest that improved polymeric dielectric materials can be designed by including −OH groups on the chain, but the mechanism requires the presence of a stoichiometric quantity of hydration water.

A kind of clay with fibrous morphology, attapulgite (AT), was used to prepare poly (ethylene terephthalate) (PET)/AT nanocomposites via in situ polymerization. Attapulgite was modified with Hexadecyltriphenylphosphonium bromide and silane coupling agent (3-glycidoxypropltrimethoxysilane) to increase the dispersion of clay particles in polymer matrix and the interaction between clay particles and polymer matrix. FTIR and TGA test of the organic-AT particles investigated the thermal stability and the loading quantity of organic reagents. XRD patterns and SEM micrographs showed that the organic modification was processed on the surface of rod-like crystals and did not shift the crystal structure of silicate. For PET/AT nanocomposites, it was revealed in TEM that the fibrous clay can be well dispersed in polymer matrix with the rod-like crystals in the range of nanometer scale. The diameter of rod-like crystal is about 20 nm and the length is near to 500 nm. The addition of the clay particles can enhance the thermal stability and crystallization rate of PET. With the addition of AT in PET matrix, the flexural modulus of those composites was also increased markedly.

This paper discusses a new class of proton exchange membranes (PEMs) that are based on a wellcontrolled polyolefin graft copolymer containing a polyethylene (PE) backbone and several sulfonated poly(arylene ether sulfone) (s-PAES) side chains. The chemistry involves a graft-onto reaction between high molecular weight PE with few pendent benzyl bromide groups and poly(arylene ether sulfone) (PAES) with two terminal phenol groups. The resulting PE-g-PAES graft copolymer, with predetermined backbone molecular weight, graft density, and graft length, was solution-cast into uniform film (thickness 20−40 μm), followed by a heterogeneous sulfonation reaction of PAES side chains to obtain the desired PE-g-s-PAES PEMs with a high sulfonation level. The unique combination of hydrophobicity, semicrystallinity, and high molecular weight of the PE backbone offers PEM with a stable (nonswellable) matrix. The embedded hydrophilic s-PAES proton-conductive domains show only moderate water uptake, even with a high ion exchange capacity (IEC >3 mmol/g in the s-PAES domains). Compared to Nafion 117, most PE-g-s-PAES PEMs show similar hydration numbers (λ <15) but higher proton conductivity (up to 160 mS/cm). More interestingly, all PE-g-s-PAES PEMs show higher through-plane conductivity than in-plane conductivity. Evidently, a thin hydrophobic PE layer is formed on the PEM surfaces due to the low surface energy of PE, resulting in anisotropic conductivity. Overall, this newly developed PE-g-s-PAES membrane offers a combination of desirable properties, including conductivity, water uptake, mechanical strength, and cost-effectiveness for fuel cell applications.

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