SynopsisThe room temperature density (pRT) of a difunctional aromatic epoxy resin cured with a tetrafunctional aromatic amine passes through a maximum value in the vicinity of gelation with increasing conversion. For a given cooling rate cure results in a unique value of pRT for each conversion as long as the material does not vitrify on cure. The occurrence of vitrification during cure eliminates the one-to-one relationship because of the nonequilibrium nature of the glass transition region and of the glassy state. In the glass transition region there is competition between physical aging which increases the density and chemical aging which, after gelation, decreases pRT. After gelation, prolonged isothermal cure and physical aging to well beyond vitrification result in limiting values of pRT which decrease with increasing temperature of cure. The maximum in the pRT vs. conversion relationship is discussed in terms of the effects of shrinkage due t o cure, the corresponding nonlinear increase in the glass transition temperature with increasing conversion after gelation, and longer relaxation times in the glass transition region with increasing crosslink density. Other factors which affect room temperature density are discussed.

SynopsisThe isothermal cure of a diglycidyl ether of bisphenol A with a tetrafunctional aromatic diamine has been studied in an attempt to achieve full cure (maximum glass transition temperature, T, , , ca. 17OOC). Since high temperatures of cure are necessary for high Tgm systems (because of low reaction rates after vitrification), cure and thermal degradation reactions often compete. In this work Tg is used as a direct measure of conversion. An approach leading to a series of iso-Tg contours in a temperature vs. time transformation (TIT) diagram, which can be used to design time-temperature cure paths leading to particular values of Tg, is discussed.

SynopsisThe dynamic mechanical behavior at about 1 Hz of a fully cured epoxy resin (maximum glass transition temperature, T , , , ca. 170°C) has been studied during and after isothermal annealing in terms of the influence of thermal prehistory, time of annealing, and temperature of annealing ( T,). Annealing temperatures ranged from Tg -15 to Tg -130°C. The rate of isothermal annealing was observed to decrease by a decade for each decade increase of annealing time when the material was far from equilibrium. Annealing at high temperatures did not measurably affect the material properties during cooling (for T < < T,); similarly the effect of annealing at low temperatures was not measurable during heating (for T > > T,).

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In this work, 3-mercapto-1-propanesulfonate (MPS) with one sulfhydryl (-HS) group and 2,3-dimercapto-1-propanesulfonate (DMPS) with two -HS groups were used as model additives to reveal the function of -HS group during copper plating. Chronopotentiometry was employed to characterize the different electrochemical behaviors of the two model additives. It indicated that DMPS showed stronger accelerating effect than MPS in the plating bath containing Cl − , which could be attributed to its enhanced adsorption caused by two -HS groups. The pre-adsorption and desorption experiments demonstrated the synergistic effects and competitive adsorption between Cl − and the model additives. Moreover, the accelerating mechanism was investigated by cyclic voltammetry combined with rotating ring-disk electrode (RRDE), demonstrating MPS could accelerate the ratedetermining step (RDS) of copper deposition only if Cl − was present, whereas DMPS could enhance the RDS whether Cl − existed or not. Finally, microvia filling experiments were carried out to evaluate the filling performance of the two model additives. The results indicated that in the plating bath containing PEG and Cl − , MPS showed good filling performance, while DMPS did poorly. However, after the introduction of JGB, the filling performance of DMPS was greatly improved, which was resulted from the competitive adsorption between DMPS and PEG being balanced by JGB.