The Cambridge dictionary says that the word 'second' is uttered as /ˈsek.ənd/, in which the first syllable is /sek/ and the second is /ənd/. My question is thus the following: why doesn't this word follow the Maximal Onset principle and get a division such as /ˈse.kənd/ in order to maximize the onset of the following syllable?
Syllable division isn't an evident phonetic fact: people disagree about where it falls (and have for quite a long time). Most arguments about this topic depend critically on which theoretical assumptions you choose to accept, as the competing theories of syllabification are underdetermined by the data that we have in the form of phonetic or experimental facts.
There are similar issues with determining the "natural" segmentation of other units of speech, such as sentences, words, and phonemes.
The basic issues with the evidence are that:
Promising-looking criteria for segmentation may disagree with each other.
when criteria agree, it's difficult to find arguments for why it is not circular to use them as tests of where syllable boundaries fall. It's not obvious what size or shape meaningful units of speech should be, and how many levels of organization we are dealing with: maybe the criteria we've identified aren't actually about the placement of "syllable" boundaries but about the boundaries of some similar but distinct larger (or smaller) unit such as "feet".
Theories that don't accept the maximal-onset principle for English
A good place to start to read more about arguments against maximizing onsets in English syllabification is "Syllabification and allophony", by John C. Wells (originally published in Susan Ramsaran (ed.), Studies in the pronunciation of English, A commemorative volume in honour of A.C. Gimson (London and New York: Routledge, 1990)).
There are phonologists who maintain that English maximizes syllable onsets, and so would syllabify "second" as /ˈsɛ.kənd/
Contrary to user6726's answer, I think there are in fact phonologists who treat English as maximizing syllable onsets (or avoiding empty onsets) in this context.
In "An amphichronic approach to English syllabification" (2013), Ricardo Bermúdez-Otero argues that starting in Middle English, word-final consonants may be resyllabified into the onset of a following vowel-initial word.
Bermúdez-Otero proposes that English syllabification is cyclical and onset-maximal at all levels (§34: "Therefore, word-final consonants are in the coda at the word level, but they are detached from the coda and resyllabified into the onset at the phrase level when followed by a vowel-initial word", page 9). This is not a case of Strict CV theory. Read the linked paper for the arguments and syllable diagrams.
There is no definitive answer to this question: there are multiple theories. The disposition of intervocalic consonants after a stressed vowel is highly controversial. One theory is that the consonant is ambisyllabic (coda of σ1 and onset of σ2). A competing theory is that the consonant is in the coda of σ1 and there is no onset for σ2. A third possibility is that it is exclusively in the onset of σ2: as far as I know, that theory isn't adhered to by any subset of phonologists who believe in the syllable (but Strict CV theory, which does not have the syllable at all, "talks" about syllables in the sense of explaining how syllable-like concepts are modeled in the theory).
Those phonologists who aren't also phoneticians often like to do away with physical data and claim instead that everything to do with syllable boundaries is down to abstract theories.
In fact there are very often a host of very good reasons to analyse syllable structure as being a certain way precisely because of the physical evidence.
Such data for English include considerations of phenomena such as aspiration, pre-fortis clipping, glottalization, dark and clear [l], other allophones sensitive to their place in the syllable, the combining (or not) of /tr/ into an affricate and so on and so forth.
One of the reasons for placing the /k/ in the word /seknd/ in the first syllable is that the /e/ there is subject to pre-fortis clipping. In other words, it is pronounced with a shorter /e/ than it would be if the /k/ wasn't there, was a lenis consonant (i.e. voiced), or belonged in the second syllable.