PMMA adhesive

The schematic processing steps for the two-layer deep-UV PCM system are shown in Table III for near-UV and e-beam exposures, resulting in capped and uncapped profiles respectively. Step 5a is required only for near-UV exposures to average out optical interference effects discussed in Section 6.2.a. Step 6a is used to enhance the AZ to PMMA adhesion and cap retention. Figure 15 shows uncapped 1 - nm lines in a 2 - /im thick PMMA layer. Figure 16 shows the capped image with 0.3 fim AZ on 2 -iLim PMMA. The AZ layer was delineated by a 30 - /iC/cm 25 - keV e-beam in both cases. 

Fig. 7 The initial test result of the combinatorial edge delamination test for PMMA adhesion to silicon substrate.

The applying was carried out by means of a form which had been produced for this purpose, in order to achieve constant layer thicknesses. The stone slices were pre-wetted to achieve an as good as possible adhesive bond. After 24 h the samples were demoulded and stored in normal climate. After 28 days steel testing stamps were applied on both sides of the samples by means of a PMMA-adhesive. The samples then underwent a tensile test by means of the universal testing device TIRAtest 28100. The samples were fixed lateral-force-free. The testing speed was 100 N/s. A testing series consisted of 4 individual samples. 

Plasma Etching, Fig. 8 SEM images of (a) an electroplated Ni mold, (b) hot embossed PMMA replica, and (c)PMMA adhesive bonding in ICP LIGA... 

The cured polymers are hard, clear, and glassy thermoplastic resins with high tensile strengths. The polymers, because of their highly polar stmcture, exhibit excellent adhesion to a wide variety of substrate combinations. They tend to be somewhat britde and have only low to moderate impact and peel strengths. The addition of fillers such as poly (methyl methacrylate) (PMMA) reduces the brittleness somewhat. Newer formulations are now available that contain dissolved elastomeric materials of various types. These mbber-modifted products have been found to offer adhesive bonds of considerably improved toughness (3,4). 

Fig. 13. Measurement of surface energies of PS and PMMA. It can be seen that there was a finite adhesion hysteresis. At a given load, the contact radius during loading was less than the contact radius during unloading. From the unloading data, we get yi>s = 45 1 mJ/nr, and yi),viMA = 53 1 mj/m . These number are in good agreement with the values of surface energies determined from the pull-off force measured using the SFA.

Fig. 14. Measurement of adhesion between PDMS and PS, and PDMS and PMMA. It can be seen that there was no adhesion hysteresis. The contact radius at a given load, during loading and unloading was the same. From these data, we get WpoMs-ps = 49 3 mJ/m-, and Tfdm.s-fm.ma = 57 1 mJ/m-.

Char, K., Brown, H.R. and Deline, V.R., Effects of a diblock copolymer on adhesion between immiscible polymers, 2. PS-PMMA copolymer between PPO and PMMA. Macromolecules, 26(16), 4164-4171 (1993). 

Leadley and Watts used monochromaticized A1K radiation to investigate the interactions that were responsible for adhesion between polymers and substrates [24]. When polymethylmethacrylate (PMMA) was adsorbed onto silicon substrates, the C(ls) spectrum shown in Fig. 21a was obtained. Originally, it was... 

Friedrich et al. also used XPS to investigate the mechanisms responsible for adhesion between evaporated metal films and polymer substrates [28]. They suggested that the products formed at the metal/polymer interface were determined by redox reactions occurring between the metal and polymer. In particular, it was shown that carbonyl groups in polymers could react with chromium. Thus, a layer of chromium that was 0.4 nm in thickness decreased the carbonyl content on the surface of polyethylene terephthalate (PET) or polymethylmethacrylate (PMMA) by about 8% but decreased the carbonyl content on the surface of polycarbonate (PC) by 77%. The C(ls) and 0(ls) spectra of PC before and after evaporation of chromium onto the surface are shown in Fig. 22. Before evaporation of chromium, the C(ls) spectra consisted of two components near 284.6 eV that were assigned to carbon atoms in the benzene rings and in the methyl groups. Two additional... 

These effects have been found by Creton et al. [79] who laminated sheets of incompatible polymers, PMMA and PPO, and studied the adhesion using a double cantilever beam test to evaluate fracture toughness Fc. For the original laminate Fc was only 2 J/m, but when interface reinforced with increasing amounts of a symmetrical P.M.M.A.-P.S. diblock copolymer of high degree of polymerisation (A > A e), the fracture toughness increased to around 170 J/m, and then fell to a steady value of 70 J/m (Fig. 9). 

An example of this improvement in toughness can be demonstrated by the addition of Vamac B-124, an ethylene/methyl acrylate copolymer from DuPont, to ethyl cyanoacrylate [24-26]. Three model instant adhesive formulations, a control without any polymeric additive (A), a formulation with poly(methyl methacrylate) (PMMA) (B), and a formulation with Vamac B-124 (C), are shown in Table 4. The formulation with PMMA, a thermoplastic which is added to modify viscosity, was included to determine if the addition of any polymer, not only rubbers, could improve the toughness properties of an alkyl cyanoacrylate instant adhesive. To demonstrate an improvement in toughness, the three formulations were tested for impact strength, 180° peel strength, and lapshear adhesive strength on steel specimens, before and after thermal exposure at 121°C. 

The data also demonstrate that the addition of the thermoplastic, PMMA, does not have the significant effect on the toughness or adhesion properties as does the addition of the rubber, Vamac B-124. Clearly, the physical properties of the polymeric additive determine the magnitude of the adhesive physical property modifications, which result from their addition to an alkyl cyanoacrylate monomer. 

Acrylic resins (Perspex, PMMA, Paraloid) -1930 Varnishes, adhesives, glazing, sculptures, paint media Sensitivity to sunlight. Methacrylates are subjected to bond cleavage. Acrylates undergo cross linking reactions... 

Fig. 12.7 InGaAsP/InP multi quantum well semiconductor structure process (a) Si02 etch mask deposition (b) PMMA spin coating (c) E beam lithography and develop (d) Si02 etch (e) PMMA stripping (f) InGaAsP membrane etch (g) Si02 stripping (h) Chip flipping and bonding to sapphire (i) InP substrate etch (j) Adhesive etch...

Consideration of the relationship between the effects of radiation on homopolymers and copolymers raises the question of the variation from homopolymer behaviour with sequence length. Every copolymer has a distribution of sequence lengths for each comonomer. At what minimum sequence length does methyl methacrylate not show the high scission of PMMA The future will probably see the development of processes for making polymers with controlled mini-block sequences to maximize a number of properties such as scission yield, adhesion, flexural strength, Tg.. 

Latex adhesives Latex adhesives are based on polymer latexes and require that the polymers be near their Tg so that they can flow and provide good surface contact when the water evaporates. It is not surprising that the same polymers that are useful as latex paints are also useful as latex adhesives (such as PMMA). Latex adhesives are widely employed for bonding pile to carpet backings. 

In the medical field, UV curable adhesives are used in fhe assembly of medical devices, such as syringes, valves, manifolds for filtering equipmenf, and arteriographs. In these applications, many dissimilar substrates, such as stainless steel, aluminum, glass, polycarbonate, polymethyl methacrylate (PMMA), PVC, and other thermoplastics, are bonded. ... 

---