Syndiotactic polystyrene was lightly sulfonated in 1,2,4-trichlorobenzene using acyl sulfate complexes. The sulfonation efficiency of the acyl sulfate increased significantly when anhydrides containing long aliphatic groups were used to complex sulfuric acid. The high sulfonation efficiencies, relative to acetyl sulfate, were attributed to the increased solubility of the longer hydrocarbon complexes in trichlorobenzene. The incorporation of small quantities (less 3.4 mol %) of sulfonic acid groups onto the syndiotactic polystyrene backbone was found to have little effect on the glass transition temperatures of these new materials. However, a much more pronounced effect of sulfonation was observed in the ionomer crystallization. Increasing the level of sulfonation decreased the melting point, degree of crystallinity, and apparent rate of crystallization due to a rejection of sulfonated styrene units from the crystalline domains.

Matrix-assisted laser desorption ionization (MALDI) mass spectrometry was utilized to determine the hard segment length distribution in poly(urea-urethane)s. Although hard segment length is expected to vary with water content in the initial formulations, the actual distribution is rather similar for all samples analyzed. A more detailed analysis, however, revealed that the principal difference is in the region corresponding to hard segments with greater than eight urea repeat units. This finding has implications for both in the origin of phase separation behavior and the mechanical performance of phase separated heterogeneous polymers. The similarity in hard segment distribution suggests that phase separation behavior in these polyurethane foams cannot be due solely to the orientational entropic contribution. The presence of these long hard segments, although not extensive (7% of the total number fraction), may contribute significantly to mechanical performance. MALDI also revealed the presence of side products. The amount of cyclic species, either isocyanurate or cyclic hard segments, varied from 2 to 4% for foams with different urea contents.

A series of polyurea urethanes was isothermally synthesized from toluene diisocyanate (TDI), water, and trifunctional poly(propylene oxide) in the temperature range of 50–150°C. Morphologies of the samples vary significantly as a function of reaction temperature. In this system, phase separation competes with polymerization and crosslinking. Both transmission electron microscopy and atomic force microscopy have shown a network type of structure for the 50°C samples, while the 150°C samples appear to be homogeneous. Infrared analysis shows that samples prepared at 150°C possess a morphology that is less strongly hydrogen bonded and has a broader distribution of hydrogen‐bonded states compared to those prepared at lower temperatures. From this combination of techniques, it can be inferred that phase separation occurs faster than crosslinking at low temperatures; consequently, a phase‐separated morphology forms. In contrast, crosslinking occurs faster than phase separation at higher reaction temperatures. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 3065–3077, 1998

Superabsorbent polymers have been around for nearly half a century. Presently, petroleum-based polyacrylic acid-type polymers are used in the majority of superabsorbent applications and markets. However, the rising costs of petroleum and the lack of a sustainable supply of fossil-based chemicals is driving a need for alternative, renewable based chemicals. Herein, we report the synthesis and superabsorbent properties of novel polymers derived from nature. Free-radical, emulsion polymerization methods were used to generate cross-linked polyacrylates containing lactone functionality, which were saponified into the corresponding cross-linked ionomers in a second step. The final cross-linked products displayed >50× absorption of water per weight of polymer and absorption under load of >15× the weight of saline solution per weight of polymer. The technology also offers the opportunity to perform additional chemistry and modification to the polymer backbone in order to improve its properties.

The continual drive for faster interconnects requires the development of new interlayer dielectricmaterials with k values less than 2.1. Porous SiLKTM semiconductor dielectric resin wasdeveloped to achieve these low dielectric constants by introducing nanometer-sized pores intothe dense SiLK resin matrix. A quantitative description of the nano-porous morphology in low-kinterlayer dielectrics can be difficult to achieve for many reasons, including: complexities in theporous structure (size range, geometry, pore/pore interaction), inadequate mathematicaldescriptors, limitations of existing metrology technology, and availability of “tailor-made” experimental samples with a wide range of pore morphologies. On-wafer quantification of poremorphology is even more difficult as data must be obtained from extremely limited samplevolumes (thin films of ∼100-500 nm) residing on thick silicon (Si) wafer substrates.This paper will focus on the design, development and successful application of on-wafer smallangle x-ray scattering (SAXS) technology to characterize the morphology of porous SiLK resin.It will be demonstrated, by example, that this technology is able to deliver rapid quantificationover the entire pore size range for these systems. Recently developed data acquisition, reductionand analysis tools will be described. Direct evaluation of the strengths and challenges of severalmodels used to generate average pore size and pore size distribution will be reviewed. Finally,additional capabilities offered by this technology (wafer mapping and detection of “killer” pores)will also be discussed.